2 cts
To answer the OP's question, I guess it depends on your desired configuration. Solo, with Pillion, Bike to Bike, Groups or even Marshalls, lead and tail man?
I have had an autocom setup but that was too fiddly with wires. Perhaps I would be better off with a non bike powered (9V) Autocom unit in my jacket pocket, so I can leave the bike and still continue comms with the helmet on.
This is important if there's an accident and you want to call for help as well as assist.
But after going BT, I never turned back. Yes, there were issues with not having bike power, VOX and multiple aux inputs, but the newer BT systems are, IMHO, better for my needs.
Yes, sound quality, noise cancelling and auto speed sensing are lacking but I have had good clear conversations on my BT headsets. Besides, who can or should talk at a 120mph?
With a GPS app (Garmin or Sygic), music and calls on my smartphone (Iphone), I did away with an MP3 player and GPS, combining it all to a phone that's BT.
Some systems allow up to six riders to communicate with each other by BT but the range is limited. Some systems require you to switch manually between MP3 and Intercom with only phone calls cutting in as a first priority. Terms such as A2DP, AVRCP, BT3.0, EDR and HFP will tell you their capabilities.
A BT battery lasts 7 to 9 hours, so in my case, a full day's riding.
To be fully functional like with an Autocom, you'll need a BT hub, like that of Sena's SR10 or UClear WT300. This is especially so if you wish to use a two way radio. A wireless PTT is available on the UClear, but there's always a lag, just like VOX.
Some cheaper alternatives are out there like Lexin
(
http://www.ebay.com/itm/LEXINMOTO-M...Parts_Accessories&vxp=mtr&hash=item4ac510000d)
and
Dellking
(
http://dellking.en.made-in-china.co...tooth-Remote-Control-Finger-Ptt-BTR-001-.html)
I have purchased several products from the Chinese Manufacturers and have not had a bad experience.
Lastly, new two way radios from Midlands and Motorola now have built in BT and wireless PTT, so that provides another alternative.
Or you could buy all the BT modules that Autocom has in their catalog and attach them to your unit. You do the math on costs.
I won't go on a long ride without music. And if an email or message comes in, there are applications like Drivesafe.ly, that turns text into speech and reads it out to you. How cool is that?