I've done a side to side with a Ribeye cooked on my Gas Grill (a BBQ-Galore Turbo model) vs one cooked on the BGE.
Basically, the steaks were seared for about 2 minutes on each side, then heat was turned down, and they were cooked to medium. Maybe a total of ~10 minutes cook time, IIRC.
The charcoal made a slight difference in the taste, which I wasn't expecting for a relatively short cook. I really thought that there wouldn't be any difference.
I prefer the charcoal taste. But, the one cooked on my gas grill was damn good too.
So yes, there is a difference in my hands, but it was slight. And both steaks were good.