In reply to Donnie: Some climbers don't like the twin stem design as the stems can twist in some placements and produce some torque which, it is claimed by some, can weaken the placement and permanently distort the wires.
The smaller 3CU are really rather good. Design-wise they're slightly outclassed these days by Zeros and the like but for the money they're great.
The 4CU are good solid cams and great value. The main problem is it's relatively easy to kink the stems so if you actually fall a lot then bendy single stem devices for a bit more money might outlast them.
In reply to jkarran:
unfortunately they've stopped making 3cu under size 1, and are completely phasing out 3CU's in the near future. To my mind the two smallest sizes they no longer make should be the most useful, although the headwidth is actually not all that much narrower than the latest model of the 4cus in those sizes anyway now.