Interesting thread so far with apparently mixed results. That is not my experience.
My configuration is a Sena SMH10 Headset (ear bud mount), Sena SR10, iPhone 4, iPad 1, Zumo 450. and a Yaesu VX-6R.
Let's start with the easy stuff. Bike2Bike using the Yaesu was PERFECT. My riding buddy said I'd never been clearer and none of having the mic pressed against your lips to be heard (Autocom issue). There was a short delay before the channel opens up the 1st time you speak, but after the talk gets started everything is instant. (Note: you can force the audio channel open full time at some cost of battery life. In normal mode I never got a low battery waning during 7-9 hour days with full time music and a lot of Bike2Bike chatter.) We were both very impressed. BTW, this was our experience whether the chin bar was up or down. Of course mine sits behind a very quiet Givi Windscreen.
Also, I connected the Yaesu using a Yaesu CT-91 Microphone Adapter and Sena's ICOM cable. This was a no-brainer for me since I keep 3 CT-91s in the tank bag (buddies are always loosing theirs). It was my standard connection method with my Autocom. It connects easily and maintains the Yaesu's submersibility.
Initial pairing took a bit of learning. The Sena documentation is good for each unit but they do not do a good job of telling you how things work together in various configurations.
After half a day of trial and error, here's what I ended up with: IPad and SR10 paired to the SMH10. Nothing special was required. Zumo and the Yaesu were hard wired to the SR10. The iPhone was selectively paired to the SR10.
With this configuration I had:
Music (from the iPad)
Phone (I did not try voice dialing since the iPhone 4 does a crappy job of that for me.)
All in all I was very pleased and would give this setup a 4 out of 5 for performance, 3 for setup though it's very easy once you've done it a few times. The SR10s get an easy 4 which I consider pretty damn good for a first iteration, The SMH10 gets a 5 but the earbud helmet mount gets a 2 (see below).
I do have a negative comment on the earbud style helmet mount (SMH-A0303). The earbuds connect via a small 3.5mm jack that extends off the lower rear of the mount. Mine has already broken loose. I would have preferred a flush jack like the MP3 input jack. I'll be applying some JB Weld to re-secure it as it still works and just needs to be reattached.
This setup meets my needs very well. It's compact, efficient and of generally high quality. There are issues with the iPhone when trying the Sena "split function" setup with iPhone music streaming to the headset and phone through the SR10. Sena says that this is an issue with the iPhone which does not like to bluetooth to two devices at the same time. I'm inclined to point the finger to the iPhone as well. I doubt it was designed for this type of use. Since I usually travel with iPad as well my configuration makes it no big deal.
FWIW, after Kirk and I spit to go our separate ways home, I re-paired the iPhone directly to the SMH10 and turned off the SR10. Of course I lost navigation but I didn't need it anyway. Pairing the iPhone (normal pairing) to the SMH10 gave me both phone and music. If the SR10 is on and paired you lose the phone function so when I'm traveling alone SMH10 pairing only will be my standard as all I will need is phone and music.