Beemer,
I've had one of these for a month or so and I'm very pleased with it. I'd tried Autocom/Intaride and for various reasons they didn't do quite what I wanted.
Set-up I have is:
Nokia 6300 blue-tooth'd to Zumo 550 which is wire connected to the Starcom Digital using their isolated 3.5+2.5 jacks (Zumo end) to 3.5 jack (Starcom Digital rider phone input). Also I've got a Nano mounted next to the Zumo and connected to the intercom rider music input via the supplied 3.5 to 3.5 jack lead (got fed up phaffing with the Zumo MP3 lark and the quality/volume is questionable anyway)
Initially I got their in-ear (PP010?) phones and the headset lead to suit (microphone with headphone socket instead of speakers) but (because I normally use custom moulded earplugs (not phones)) I found that the PP010's let far too much wind noise in, even at 40mph. I've now reverted to their normal headset (mic and speakers) which I use with my custom plugs. I actually opted for their PP024 headset which you won't find on their site but they can supply it; this has both mic and speakers but also has a 3.5 jack socket incorporated in case you want to later use custom moulded earPHONES (e.g. from UltimateEar etc.). Best of both worlds I think.
Performance? Intercom/Music/Phone all work perfectly. I've used the phone at around 70-and-a-bit

and conversation was fine. Once you're up to those sorts of speeds using earplugs and speakers then, regardless of make (trust me I've tried them), the music etc. is getting a little overpowered by the rest of the biking cacophony. The range of settings for individual volumes/vox sensitivity etc. for both rider and pillion is great and of course rider/pillion can have independant MP3 and/or phone connections. The icing on the cake for any of these systems of course would be UltimateEar custom moulded phones but I can't quite stretch to that yet.
I've only one minor gripe with the system and that is that the intercom vox/music mute cuts in intermittantly now and again at motorway speeds - but then I'm wearing an Arai (noisier than most) and riding a GS1200 and we all know how windy/buffety they are - I'm awaiting NN High/Wide screen and winglets so that might improve. I've set the mic sensitivity to 'Hi' (harder to activate) but it still does it.
Overall I'm very pleased and would recommend it. We're off to tour France/Switzerland/Germany in July so it will pay for itself...kinda!
Sorry for the 'War & Peace' reply but I thought you'd benefit from as much info as possible. Download the user manual from their site and have a good read - it tells you a lot about its capabilities.