Not with the HD800. I heard one with HD650 off Bottlehead's tape rig at RMAF 2011 and was completely underwhelmed. I believe it was a Crack w/ Speedball, but it could have been the standard. I don't recall. I don't intend to own a Bottlehead product based on that experience. I'd be willing to give one another try at a meet/etc, though.
I own a few Bottlehead products in the Crack and Quickie. I also used to own the Woo Audio WA7, the only other tube amp I've tried. I also used to have the HD700, and I found the WA7 to sound slightly better than the Crack for the HD700. The Crack did sound better for my Beyerdynamic T90 than WA7. I have sold both the HD700 and WA7 since, so I can't compare directly or use the WA7 with HD800. I got the Bottlehead Quickie later on to use for my speaker amp setup for my HE-500. I got my HD800 about a week ago, and really only had the Crack to drive them, and it sounded okay. Out of curiously, I tried the HD800 with my HE-500 setup (Quickie + Emotiva), and while it had some noise floor issues, I was quite surprised when it sounded better than the Crack for the HD800! For one the sound became much more intimate and engaging, especially vocals. I reported this find on the Bottlehead forums and was encouraged to try the Quickie with the Crack. I was hesitant at first because I had never heard of using a preamp with a headphone amp, but to my surprise, not only did it sound even better than Quickie + Emotiva, it had a dead silent noise floor. So right now I'm using Quickie + Crack to drive my HD800, and it's sounding very musical and engaging. Comparing Quickie + Crack with Crack alone for the HD800, the difference is quite significant. I tried the HD800 with just the Emotiva alone, and as others have reported with that pairing, it sounded pretty bad. But the fact the Quickie + Emotiva was even better than Crack alone for the HD800, and also the significant improvement from adding the Quickie to the Crack made, has me concluding that the Quickie is pulling a lot a weight in the sound of my chain for the HD800.