Just picked up both a ba200 and the ie800.
Some quick impressions:
As far as comfort, I think both are very comfortable. I wear the cable over the ears for both but the ie800 also allows you to wear them down.
I really like the flat cable over the ears since it seems to lay down easier. I also wear glasses so this is great and there isn't too much interference.
I have yet to try to be active in them but I jumped around and they stuck behind the ears just fine. The IE800's housing makes it easier to pull it out of the ear, but the BA200 is easier inserting into the ear due to the smaller nozzle.
The Y on the ba200 isn't as big as I expected. Some of the pictures made it look large. There also isn't that much weight to the Y junction and the extension connector is arguably heavier.
IE800 requires a bit more volume on the sansa clip zip than the BA200. Not that much more. Anyway, so far I'm enjoying both.
can you give us your impressions on the sound differences and what you like about each one in terms of the particulars in the sound. Like X headphone sounds wider (greater soundstage), Y sounds clearer and more detailed, X has more treble, etc.