To answer your question: YES...there is a HUGE difference in tubes.
JJs are an inexpensive & safe bet....as are the Mesa branded tubes for your Rec.
I'd avoid Ebay unless they're from a dealer with some type of return policy & a bunch of good feedback.
ALSO go to this site & read up on the different tubes:
www.guitaramplifierblueprinting.com
:beerchug: