Eh, I don't really care for the Tubemeister series, they're more purpose built for jazz and blues.. The ones I've played have never impressed me on the OD. If you're looking for metal, you cant beat the 6505. If it were me, I'd just spend the extra 70 or so bucks and buy the 6505 MH. You can definitely get crunch out of the Tubemeister, but the 6505 is a whole different beast. It really depends on what styles you prefer.
Further correction- It looks like the Tubemeister costs more new.