It is widely reviewed and recognized as a Clifton with a nubby tread slapped on the bottom. CATR works well for me on trail where it helps to have a little extra grip. Slippery mud, wet wood/bridges, light gravel all seem to challenge me (get it) less with the CATR. I used them on a rocky trail this past week, and they had enough midsole so the sharp rocks couldn't touch me.
I didn't love the Clifton. I felt it was a little too flimsy in the upper, I didn't like the lightweight tongue. Didn't hold my foot well - it was very sloppy. Some of the things that annoyed me in the road Clifton worked in the trail CATR - the thin tongue, though a challenge to lacing, keeps a lot of detritus out of your shoe. And the extra room is less of a problem when your feet swell up a bit from the heat and pounding. The roominess in the CATR was also minimized by me by using both inserts -- putting the Ortholite insert under the standard one).
So, I was all excited about the Clifton 2. It promised a thicker tongue, a more substantial upper, with little added weight. According to the website:
For 2015, the award-winning Clifton receives an updated upper with a focus on lightweight comfort in the CLIFTON 2. A softer, lightly padded tongue provides increased protection across the foot, and structural overlays improve midfoot support. The industry-leading ride remains unchanged, and the road-focused outsole includes strategically placed rubber pods to improve durability. When all is said and done, one of our favorite shoes just got better.
Tongue - check. My kind of tongue - not crazy thick like a New Balance, not crazy thin like the Clifton. Works like a charm - meaning you don't have to lace to cut your blood supply off your feet, or lace so loose that there's barely any lace left.
Overlays - check. It seems at first wear they might have gone too far in the structured direction, but after 10 miles, it softened up nicely. The added support is welcome - didn't find my foot all over the place - whether on road, dirt, mud, roots, etc. Doesn't have a ton of room so it might be better at the beginning instead of the end of the race...
Rubber pods - we will see. Placed sensibly but who knows how it will hold up until the miles go down...
I'd have to say the 2 is better than the 1s. Much better.
I'm not sure I will ditch the CATRs for more challenging trails, but for running the flat/dirt/gravel of the C&O for at least half of my miles, the Clifton 2s have more than enough grip. It feels a little higher riding - a little less ground feel - compared to the CATRs. But I think they are good enough for most/all non-technical trails I run.
The only bad thing I can say is that the forefoot could have been a teensy bigger. But I had no problems with hotspots, etc., and it feels like it is stretching out with progressively more miles.
Also see RoadTrailRun review
Update 6/18: 32 miles into them, and I'm not as hot on them as I was. I feel the rocker a lot more on the Clifton 2s... I don't feel them on the CATRs. I assume this is because of the generally less cush nature of the CATRs.
Also: feeling it in my left shin from the rocker. Hopefully this is just the adjustment to the rocker and not the beginning of a return of shin splints.
Finally: one strip of overlay on the left inside shoe is separating from the mesh. Not that happy with that happening at all... these kind of things seem to happen on the first production runs with a lot of shoes.
Anyway, its not the promised land. Still a solid shoe, and an improvement on the 1.
Also: see review of Challenger ATR 2.