While I applaud the effort and hope it works as advertised I'd be lying if I said a whole bunch of big red warning lights weren't going off inside my head.
My issues aren't due to 'wifi' privacy issues but you SHOULD give that some though, however my misgivings deal with the process itself. Contrary to what some may think, Syncing by any means is an ENORMOUSLY difficult task.
Anyone who suffered thu the YEARS of iSync ... growing pains ... can agree with me when I say, it's a tough thing to get right. Along the way, be prepared for duplicating or triplicating (or more) your Address Book entires and/or your iCal items. Also be ready to deal with the possibility that one or more of your datasets (cal-data, address-data, etc) gets wiped out and the gets propagated to any/all other devices you are syncing with (via Apples iSync or 3rd party sync products).
In short: Have lots and lots of backups... in places where the files are NOT synced by anything.
It certainly seems like a no-brainer but there are A LOT of variables to account for, as well as A LOT of 'unexpected actions' all or any of which could FUBAR your life.
It took me a LONG time to finally trust iSync would behave and simply set it and forget it. Jumping into a new APP ... I'd wait for LOTS and LOTS and LOTS of 3rd party reviews (did I say LOTS) before I'd even consider looking at it.