Over the years, I've owned at least seven pairs of rollerskis of various makes and models, and I've tried numerous others. The V2 Aero skating rollerski from Jenex comes closest to my idea of the perfect skating-only rollerski. 

Unlike other rollerskis, the V2 Aero 150S uses a 150mm diameter pneumatic wheel. You use a bicycle pump to adjust the pressure between 55 and 90 PSI; the higher the pressure, the faster the ski. The wheels are 31mm wide. Other rollerskis typically have widths of 33 to 50mm and much smaller diameter (e.g., 70mm). 

Performance
These rollerskis do have the most snow-ski-like feel of any rollerski I've skied. If you don't push off correctly, the skis tend to plow. There's also a slight give when pushing down on them that feels like pushing into the snow. You really notice it the first time you ski them. 

They are also pretty darn fast, but adjustable. Most people I know pump them up to the 90 PSI and fly. I prefer to keep them at the low end (55 to 60 PSI) to slow them down. At 60 PSI, rollerskiers with fast wheels still tend to be slightly faster. 

Balance is more of an issue. At 31mm wide and 150mm in diameter, these skis are somewhat tipsy compared to regular rollerskis. The vast majority of people I've talked said it took a couple times out to feel comfortable on them, but that they'd never go back to their old skis afterwards. People with narrow feet swimming inside too wide boots (like me) may take a little longer getting used them, particularly when going fast. 

Beginners? Although the web site doesn't recommend them for beginning rollerskiers, I've seen beginners use them with success. It helps - a lot - if they're decent skiers on snow. 

Whoa Nelly!
The speed reducers very effectively tame any downhill (and I've been down a couple steep ones). I've never had to use the slowest setting - my guess is that you'd almost have to walk down the hill with it! I haven't snowplowed much but my initial impression has been that the Aeros don't snowplow as well as the smaller wheel skis. 

The directions that come with the speed reducers specifically say not to use the speed reducers while skating. Since I occasionally want to slow them down while I skiing with others, this seemed like to problem. I sent an e-mail off to ask what the really issue was. Len Johnson from Jenex quickly replied: 

"What happened was that many people put them on too many clicks. The wheel would stop each time they lifted their skate ski, then the wheel, now locked with resistance, tried to go from zero velocity to the skier's road velocity in nanoseconds and of course the wheel can't do that so it would skid a bit before rotating at full speed. The result was that skiers developed flat spots on their wheels. One wheel sent to us looked like an octagon. If you use common sense and use the speed reducer on the first or second resistance position it can work."

Len's right, the wheels do stop turning, but I've used the speed reducer in the first position with seemingly no ill effects. I occasionally use the second position. 

Road salt, twigs, rocks, and rain
A perfect 10! These "big wheels" really smooth out the rough sections. A couple stories will illustrate: 

• John Stoy and I went rollerskiing toward the end of last winter. The bike path of Kensington Metropark was covered in road salt. With his "little wheels", John feared for his life - he had to carefully negotiate around the bigger piles and keep his weight back so his front wheel wouldn't suddenly catch on individual salt crystals and cause him to fall. He almost turned around. Me? It was as if the salt wasn't even there. I had zero issues and zero worry.
• In the spring, a rainstorm caught me. I slowed down - typically rollerskiing become treacherous on wet pavement, especially on the painted centerlines. To my joy, I discovered that the Aeros never slipped, even on the painted lines! Now, I must admit that the wheels were still in almost new shape, with lots or tread. I have not been in the rain with well-worn (i.e., bald) wheels yet. When I do, I'll update this article and tell you how it went.
• The long wooden bridge at Kensington Metropark is constructed of 2x4s. Rolling over the bridge on normal rollerskis is a matter of shake, rattle and roll. (On inline skates, my feet shake so much, they lose feeling). On the V2 Aeros, only a small bit of roughness is transmitted to you feet - the pneumatic wheels absorb most of it.
• On my recent rollerski between Boyne Mountain and East Jordan, I safely skied over M32's rough pavement and pebbles on the paved shoulder. 

Small twigs: not a problem. Small stones: not a problem. Rolling off the pavement onto the grass: not much of a problem - much less than other rollerskis. I( haven't tried gravel roads yet, but Jeff Ray and Steve McGregor just invited me for back-road rollerski trip to Starbucks on V2's, so I'll report shortly...)

Wheel wear and maintenance
My own experience has been that the rear wheel wears much quicker than the front. Once the rear tires were substantially more worn than the front, I rotated front to back. 

One of the big advantages of the Aero wheels is that they wear evenly. On all previous pair of rollerski, I be constantly rotating wheels in a futile attempt to make then wear evenly. No matter what, they'd always wear into a "V" shape, or wear on one side more than the other. The uneven wear changes the ride characteristics of the ski.

I figure I have roughly 550 kilometers of rollerskiing in this season - the tires still have tread (mostly) and I'm still on the same set of tires.

I've also noticed minimal (if any) change in ground clearance. On other rollerskis, I'd need to replace the wheels because I'd bottom out over bumps or cracks in the pavement, or the shaft would hit the pavement when edging. No such problem with the Aero - not only do the wheels wear evenly, they don't seem to reduce in diameter much.

V2 Aero "Big Wheel" with some "little" brothers. All have about the same number of kilometers on them. If you look closely, you may notice how uneven the little wheels are compared to the Aero's wheel.

It's pretty obvious when to replace most rollerski tires. Either they fall apart, get rough spots, get very uneven, or wear down so low that there's not enough ground clearance for the shaft to go over typical bumps anymore. 

On the Aero, the tire has a heavy tread, and as the tire wears, the tread wears off. Was that the time to replace the tires, or could they be run bald  I asked Len. Len says, 

"Many people are not replacing them till they see the fabric all over on their tires. T Kline, at Bicycle Doctor in Wisconsin, said his tires are nothing but fabric; he said there is no rubber showing. Obviously that is not a safe method, but we have a pair of skis at the Stratton Mountain Ski School in Vermont with well over 2,500 kilometers on the tires."

Must be that 6.5 plies of "special construction" that the Jenex web site brags about...

Pump it up
Jenex sells a slightly modified Fox HP pump that works extremely well in the tight confines of the wheel (the threaded portion has been welded to the hose, so you turn the whole pump to thread it onto the valve). You can easily pump it to exactly the right pressure. I you want to save the $40 or so, try your normal pump. People with big hands may have problems.

Crash!
I fell three times this spring - and I couldn't figure why. Each time I was standing almost straight and coasting around little kids or other obstacles. I finely figured is out: I still had big snow baskets on my training poles - I had let my baskets touch the front wheels, instantly stopping the ski and sending me to the ground. Once I switched to roller ferrules, the problem went away. 

I also fell once during a pace workout. I think a collapsed my ankle inward (remember - narrow feet and wide boots), causing the ski to go on it's side. 

The bottom line
There are a couple of things that could be done to make the ski better. I'd like slower wheels (but I'm the odd person here - no one else seems to want slow wheels) and fenders to prevent splashing up my legs from wet pavement. But overall, this is a great ski. If you're on rough terrain or messy trails, this is the ski for you. Jenex has recently released a substantially lighter ski with 125mm wheels, the V2Aero 125S. If you don't plan on skiing on dirt roads, this ski might even be better.

So what does all this really mean for the rollerskier? 

For me, the V2 Aero allows me to have higher quality training sessions. I'm much more likely to go out in marginal conditions or on marginal pavement. I don't need to worry about twigs and stones when I rollerski in the dark. I can maintain my speed and effort - and heart rate - when going over rougher pavement. I don't have to dread the fall, winter, and spring when paved trails may not be swept for weeks of months.

And higher quality training = a faster race season on snow...