gps systems

does anyone know much about these devices. is this one any good. any advice ?
http://www.chainreactioncycles.com/M...?ModelID=12519

I have a 305 which is similar. Great for distance, heart rate, speed, elevation etc - plugs into your PC and gives a breakdown of each ride - comparisons with previous outings on the same course etc. Probably not great for use as a GPS for directions etc - the 605/705 series is more suitable if that is what you want

cheers for that.. that clears up a few questions i had .