Originally Posted by Ultraslide

Rollers are great for improving your pedal stroke and balance but they lack the ability to do high force, low cadence reps because of the lack of resistance. It is also very difficult to do an out of the saddle sprint or climbing effort on rollers. Ideally you'd have both roller and a trainer but if you are a casual cyclist and not a racer I'd say the Performance fluid trainer would be fine. The Cycleops Fluid 2 and Kurt Kinetic Road Machine are best of breed trainers and are easy to find on Ebay in the $250ish range, sometimes cheaper.