In my area it is a bit odd, we have probably around 25 Gamestop's in the city and around 8 Best Buy's. Best Buy has been kicking serious ass the past few years on gaming deals, with 20% GCU discount on all games (and it going on sale for $5-30 multiple times), huge inventory, no one bothering you when you shop, online ordering and in store pickup, good trade in values, etc, etc.
However every time a big game launch comes up all the gamestop's around me just wreck Best Buy in terms of customers. For both Destiny and Call of Duty I visited 2-3 gamestops and 2-3 Best Buys at midnight and the gamestops each had 100-200 people in line picking up games, while Best Buy had at most 30 or 40. I rarely see anyone with GCU. I guess people are just too stupid/ignorant to save money. Yet when something like black friday rolls around they all stand at best buy for 8+ hours to save $100 on a TV...
I still like shopping at Gamestop just to see what happens to other people. Right after Christmas they had 50% sale on guide books so I picked up a super smash CE guide for $6, while waiting in the extremely long line the family in front of me had a 14 year old kid with GTA5 for 360 and his brother with some 3DS game. Clerk starts processing them, right before the mother pays the manager walks by and says "ma'am do you know this game is rated-M and features violence, sex, and killing prostitutes?" The mom starts yelling at her kid in spanish who starts crying and begging for the game while his brother had that "haha fuck you!! look on his face", it was the greatest thing in the world.