I also use autocom. I have no idea how it compares to others, but it works perfect. I do think its manufacturing quality looks poor, and switching between bike power and battery is far too complicated. I also wish it had an on/off switch (If it does, I have not found it).
One thing though, there is a lot of plugging and unplugging wires if you have a lot of gadgets you can't live without, or you can't leave everything on your bike for lengths at a time. Items such as the gps, mp3 player, and phone, are items I like to bring with me when I leave the bike, sometimes even the radio tranceiver. Some of the items I like to take with me even for really short stops, such as the phone. It is a pain in the butt with all this plugging and unplugging, with wires and cables everywhere! In the future I hope that all these items will be produced with blue tooth wireless interfaces. I am seriously considering upgrading to a blue tooth interface for the phone and dropping all other gadgets but the transceiver. I'm also looking into purchasing a phone which double as a transceiver, but am yet to find one with blue tooth. If I was to do this again, I'd go the simler and much cheaper route, to forget about all the other gadgets and just have the transceiver, no communication box, no mp3 player, no sound from the GPS, no phone, just the bare minimum... in fact, if it was up to me, I could live with out the chit chat of the pillion or other riders.
As more and more phones come with built in GPS and MP3 players, there is a coming, in not too long, when all you will need is this one gadget. I can't wait, because I really hate, and I'm using the word hate here about technology, all this hassle with wires.