They would all be about the same for gaming. Most games can't use more than 4 cores much less using threads like 26xx and 27xx processors have.
Whichever one has the fastest speed in GHZ should probably be the best one for gaming, but they will probably all be just fine.
You get what you pay for though. If you are paying $125 less for a computer its probably because it is worth $125 less.
As long as you understand that you are fine.