The articulating skid is awesome, but a bit disappointing at the same time.
I'm really glad I got it, but it did not make the Summit into the reversing machine I was hoping it would - it is SIGNIFICANTLY more capable in reverse than when it had normal rails, but it is not a "narrow Skandic" by any stretch.
Reverse is basically useless in anything soft without them, but it did not transform the Summit into quite the exploration machine I was hoping it would; I'll go pretty much anywhere (but there, last weekend) on the Skandic - "if I can go backwards, I can go forwards." I wanted the Summit to be a lightweight recon machine that I was not afraid to take down into nasty, off camber places by myself. The Skandic is just scary in places like that - once I have a road there, it'll be fine, and chances are, the Skandic would not have gotten stuck there, but it took all I had to keep the summit level going down earlier in the day.
I really, really wonder what a TundraX is like - it does seem to be related to the "track to track" ratio - track width to ski stance. The Summit drags too much snow backwards. I bet a TundraX is really what I need.
The Summit is good, though - it just does not let me do what the SkandicSWT does, which is the whole battering ram thing. I can bash into stuff for hours on the Skandic and make progress - the Summit does not like that game. I can even sidehill the Skandic up fairly steep things - it is kinda precarious balance wise, but possible.
Anyway. I'd absolutely do it again, I do not regret the purchase/effort to install, I've not noticed any difference as far as climbing - I never lock the rails. It DOES let you back out of a hole once or twice, but you can't just put it in reverse, pin it until you hit whatever is behind you, then go forward again until you can't, repeat. It works better if you reverse just enough to get it backwards a bit and on top of the snow.
Anohter thing - I've found that the etec does not really like repeated cycles of RER.
.02c - it is really good, but not quite what I'd expected.
Iain