Another vote (from a 705 owner) for the 800. For the same price as a 510, I'd take the mapping every time, it's so useful. I've heard of more than a few issues with 510s and 810s from owners, including people I know, Garmin has an unfortunate knack of launching new devices without fixing bugs their predecessors had, plus a whole new set of problems. Sadly, the 510 & the 810 are no exception to that (and the 810 does not seem a big practical step up from the 800 either).