Monkey, I'm not sure about your comfort issues with the UEs. Mine were fine once I got the fit right, and painful before I did. I have a good seal, but no pressurized feeling except when putting them in and taking them out. I can only think it's a fit problem with yours, unless you're unusually sensitive, in which case, nothing will feel right. The JHs use the same material as the UEs as far as I can tell. I was lucky and the fit was perfect first time around. I've accidentally slept in them all night a few times now, and other than rolling over and yanking the cord once (NOT recommended), they're very comfortable.
I had the 800s here alongside the JH13s. I prefer the 13s for tone, especially bass, as well speed, imaging (instrument placement is amazing), and they have a bit more punch/attack than the Senns, which are more polite. The "soundstage" of the 800s seems larger, but who cares. Depending on the recording, I swear I'm right there if I close my eyes. Though I'm not yet ready to give up my R10s and O2s, I can see myself doing so in the future. I do plan on building a small home rig around the JH13s, and if/when I get around to it, I'll consider what I want to do with my other gear.