Have had them forever but am using other wheels due to advantages of other wheels.
If you can, get the latest version (hub looks like three solid pieces of aluminum - left, middle, right). Anything where you can see circlips or carbon in the hub, forget it.
The wheels are still illegal for UCI. I believe they're legal for USCF if they have the spoke edge protectors (look like those cheap door edge protectors for cars).
They're pretty aero, like any aero wheel they're beneficial over 28-30 mph.
They're not light (I'd say average) so they won't jump like the super light wheels you can get nowadays. They're not as aero as the very deep dish wheels (50+ mm).
They're quite strong/durable as long as you don't chip/crack/break the spokes (i.e. you crash, you pile a lot of stuff on top of the wheel, a stick ends up in your wheel, etc). The spokes don't break spontaneously.
I rode them for probably 5+ years (generations 1, 2, skipped 3, 4 - the all aluminum hub one) and on and off for another 5 years. Also rode standards, extralights (drilled out rim, ti axle), and superstiffs (extra layer carbon in spokes). x-beams make standard/xtralights like superstiffs, in a superstiff it feels like a solid disk.
Although people mention the wind, it's no worse than any deep rim wheel, it's just that back then, no one rode on them too consistently so no one was used to them. Nowadays it's sort of standard fare. They do wiggle a bit (not sure why but they do) but I never had a problem with them. I did use a front TriSpoke for most of my training for a long time so I am used to using wind-catching front wheels. Of course in the rear it's never a problem. To illustrate their user friendliness my then girlfriend (non-racer, just recreational) used a pair of my RevX's no problems for a year or so. I borrowed back a wheel for some race and promptly crashed it so now she has a matching set of normal wheels. She's my fiancee now so she must have forgiven me.
Moved to some superlight carbon deep rim wheels so slowly depleted my RevX numbers (still have one though).
I have to admit that I know the designer (he and the company were local back then). I met him when he was designing John Deere and medical supply things. He showed me a design for a disk wheel and asked me what I thought. I told him that's been done (1984 Moser, then various disk wheels after). Then a year or two later he showed me a low spoke count wheel (i.e. tri spoke, quad spoke, something like that). Specialized/DuPont had the TriSpoke (bronze in 1988 Olympic road race) out before that so I told him it's been done. Then one year he said that he had a new design, patented it, and it was going to be a hit. I don't know if it was a hit per se but a lot of pro teams rode them (Mapei and Saeco to name two - and Cipollini won a lot of races on them), they were sometimes relabeled as Ambrosio to satisfy sponsors, and for a couple years they were the hot wheel on the 'cross circuit. That designer has gone on to do the Topolino wheel, his new design idea.
hope this helps,
cdr