Its strange but if i had to voice my opinion on the matter then I would say their just about equal and that Gamestop is slightly better. EB is very close and would be THE BEST video game store if not for one reason... they rip you off on game re sales.
I got my ps2 from EB and I only had 60 bucks cash so I traded in the following:
My Gameboy Advance, Gameboy Color, 2 GBA games, 12 GB games, A PS1 (old vcr lookin ones not the PSOne) and 10 psx games,
They gave me like 70 bucks for the GBA and 5 for each game... they gave me 5 for the
GBC and like 2-4 dollars for each game for it... and 100 dollars for the PS1+10 games (their was a deal that you could bring in any 10 games and a psx and get 100$ for them) and i traded in a ps1 mem card that had 12 pages on it and a offical psx mem card. I got 50 cents for the madcats psx mem card and 1.75 for the offical mem card.( didnt know they could be used on the ps2)
Everything I sold them they marked up at least 20%... my pokemon red which they paid me 2 bucks for was up for sale for 10... alot more then 20%!!!! My GBA was like 5$ under what retail was and my Golden Sun was up for 25$. They rip you off so bad.
And one time my friend went to EB to get a new ps2 because his got DRE's and this one starting getting them to so he took it apart to find the cog wheel already marked.. and this unit was sold to him as brand new ( not refurbished.. BRAND NEW )