So I'm sure most of you already have a headset that you are happy with and couldn't care less about my search. That said, I am doing a bunch of research and testing anyway so I might as well post my findings just on the off chance that somebody else is looking.
My first two victims were the Jawbone Icon and Era. I'll say something about each and then comment on Jawbone in general. I tested them each over the course of a day a piece. I made 15 calls with each one, a very patient friend and my mom (thanks mom

). I used regular cell service as well as VOIP over 4G and wifi. The calls were made in my house, my car, walmart, on my bike and while doing various oddball things like opening and closing the garage door or running the garbage disposal. I listened to music on my phone, streaming via Music and Pandora. I also messed with Mytalk and Jawbones Android App.
Jawbone Icon:
Perfect size for a bluetooth earpiece in my opinion. It has excellent sound quality in calls and good quality for music. The further you can get the thing in your ear the better the music quality is (more on this later). The control was in good place, but I found myself hitting the button quite a bit while adjusting the earpiece.
Jawbone Era:
Good size and really nice controls. The accelerometer that allows you to just tap anywhere on the headset to answer is really nice. Sound quality was very good although surprisingly not as good as the Icon for me. Call quality was clear and music was just alright. The audio also had this odd habit of getting lower and lower while I would walk around.
Jawbone in general:
Noise Assassin on the headsets is just awesome. I was talking to people in incredibly noisy places and even causing noise and the person on the other end of the call heard nothing. Standing in my garage opening and closing the door was cool since they couldn't hear anything but my voice on the other end. This is one area where the commercials are telling the truth and I can see someone who spends a lit of time in really noisy environments getting full use out of this feature.
I consider myself to be pretty average in the ear department. I use in ear headphones with the default medium sized inserts majority of the time. These had to be the absolutely most uncomfortable earpieces I have ever worn in my life. I tried ever combination if the included adapters and even cannibalised a few older Motorola earpieces I had and nothing helped. These things are just uncomfortable, which really sucks because I liked them.
The sound on each of these with music were great if you could really get the thing in your ear. There was a fullness to the music coming out that made me almost wish they made in ear headphones with better inserts. The problem was getting in there to hear it. This is playing music through Google Music though and Pandora sounded like I was 10 feet away from the speaker. There was no depth to the sound at all. It may have been my setting on Music, but even with those turned off it was just sad on Pandora.
Mytalk and the app are junk. The packaging for these headsets is very misleading as to what they really offer. All the talk about Pandora and the other apps are just talk. They do nothing extra and offer no real enhancement to the phone or the headset experience. In Mytalk it just gives you a link to download the app for your phone like nobody had ever heard of Pandora before. It reminds me of when TomTom used to offer different voices on the GPS so you could have Mr. T or Darth Vader giving you directions. The only thing I got out of the Android app was a little battery level in my notification bar, which while cool is rather useless since I could just tap the button and the earpiece would tell me the remaining charge.
Bottom line, if the headset will fit in your ear comfortably then either one is really nice. I liked the Icon better, but they both do a great job. The overall sound is great (I had to turn the bluetooth volume almost to the bottom to keep from blowing my eardrum). The noise cancellation is unlike anything I have ever used before.
My next is the BlueAnt Q2 which is still in testing, but I can say that the earpiece is like a plush leather recliner compared to the Iron Maiden that was Jawbone.