Posted By:
Frank WakefieldAgain, you could watch eBay for a few weeks, and get a feel for it.
In looking at what Zinn and Mark L posted, I think they/Zinn has it about right.
Seems to me that SGC is a bit more exacting in what they do. PSA gets the card identity incorrect (sometimes the player, but what I mean is that sometimes they have incorrectly identified the set from which the card came). Still, a lot of folks love graded cards and all the set registry stuff, and a high grade T206 in a PSA holder may well outsell the same card in an SGC holder. Kinda like what Zinn said.
Personally, I think SGC is better than PSA. But the market for PSA cards seems stronger, so for some cards get them graded according to Zinn to maximize your sales price.
A catchy phrase there, "according to Zinn".