It's only been about two days of Playing my new MKIV. So things are not set in stone yet, but I just wanted to say that the Neo vintage sounds a lot better then the stk celestion IMHO. Now the neo is a vintage one which sounds different then the Century one. Also the neo I had laying around is a 16ohm speaker, instead of the stk 8ohms. Anyway the neo sounds a lot better on the 2nd channel. I was having a problem dialing in the 2nd channel. with the stk speaker there's a high end sizzle to the mid frequency, and I could dial it out. When I put in the Neo, it was gone. The neo has a little less highs then the stk speaker, which helps. I think the Neo gives it up a little and sounds warmer then the stk speaker. The big thing is it's early yet and the stk speaker isn't even broken in yet. I just wanted to let people know if you have a problem with the weight of the combo, that the Vintage Neo celestion sounds very good. Also the JJ 6V6's sound better then the stk 6L6's IMHO. The 6v6's have less bass and a little nicer break up, still very early to tell. I have to gig with the amp to really tell, but thought it worth a post.