Originally used OnSync for an older CDMA Samsung phone that couldn't connect via iSync, and for which Bitpim was sort of dicey (and ugly). OnSync worked perfectly immediately. Then I got rid of the older phone for a GSM Samsung, and compatibility was broken; developer was very helpful in getting it back, actually updating the application itself to add compatibility. Then I got a Razr V3 and it didn't seem I needed OnSync after all that--it works with iSync. Wrong--well, not wrong that it works, but wrong in that OnSync is much more flexible in choosing what contacts to sync (or not).