Strengths: Small watch face, ANT+ (bluetooth like) data transfer and connection to PC is fantastic, ready to use immediately (self calibrating)
Weaknesses: Not 100% waterproof (ie. probably not for triathletes) Menus system and instructions not intuitive Easy to hit start/stop/ buttons inadvertantly, particularly if cross training
Overall: I am happy with the FR50. The ability to easily download data and compare through the graph based analysis is a great tool. This is a competitively priced device offering all the critical data a runner requires - it is cheaper than the equivalent Polar - the RS200SD (although that does offer additional functionality).
The FR50 should particularly be considered by city runners who use underpasses/run near buildings where GPS signal is dodgy. Purchasers should be aware that GPS watches are coming down in price, which provide satellite-accurate data. I didn't feel that GPS devices were yet small enough to wear comfortably as a normal watch (I wear my FR50 quite regularly in the office after running in).
Make sure you buy the footpod/bike monitor together (assuming you'll require those components). like most kit, buying add-ons is, I am told, an expensive business.