Hi All,
Let me try and clear up some things about iSyncr.
iSyncr does do incremental syncs over both USB and WiFi. If you are seeing something different, that is certainly a bug (or a misconfiguration) and should be reported. At this time, there are no open issues with incremental syncs.
Laramie8x8, iSyncr does not force close your music player. However, I have seen time and time again that using iSyncr to fill a bad SD card with music can cause all sorts of strange problems on an Android device (at least one customer a day sends an email about something wrong with iSyncr that turns out to be a bad SD card). Almost all of the time, the issue is the SD card (but sometimes a bad USB cable can cause these issues). iSyncr does not inject code into a music player causing it to crash. I promise.
With that said, iSyncr should be getting an update to 2.6.3 today which will add support for the Galaxy Nexus. We got one from Europe, as Verizon/Google are just taking too long.
-Justin