I have used the teflon copper, teflon tin, and OIMP caps from V-cap.
These are very, very expensive caps, but certainly the best I have worked with sonically. I must admit, however, that the break in on the Teflon caps was more dramatic than I had expected.
I do highly recommend securing these tightly, as they are very heavy, and you can simply snap them off your leads if you leave them loose.
For a fair amount of Bottlehead products, the OIMP caps fit the bill (I'd love to hear a Crack with four 47uF OIMP's in it).
-PB