They cost the same.
They've got a few slight differences in the cone shape that make a bit of a difference in the sound. I'm under the impression that the ones I got are the modified v30 that Mesa orders.
The only other difference is that they're pre-broken-in. You usually have to get a good number of hours of playing on speakers before they start to sound their best. The guy at Avatar gets that out of the way for you in his "Hellatone" series. They're just a few select Celestion speakers that he runs something through for 15 hours straight.