No problems here with the cheaper ones from Performance Bike (TravelTrac). Simple, but work great, and enough resistance to get a solid workout if you're not just working on technique. Haven't used the Kreitler's but aside from possibly being slightly more quiet (mine aren't that noisy, but still cause a low "buzz" at speed), there aren't any features I feel I'm missing.

If I were to 'upgrade' my rollers, it would be to get the floating rollers by E-Motion with side bumpers for the safety features, but they cost 5x as much.