Gonzalez could produce some really impressive performances especially when he was younger and going for broke but he needed a specific type of opponent, one that gave him plenty of time. Hence why in their h2h meetings in that late 06-early 07 period there was no doubt as to who had the better forehand. Federer could dominate you with his forehand regardless of who you were simply because there was no counter to his FH at his peak besides retrieve every ball and make him go for too much, but only one guy on 1 surface was able to do that. He had too much power, spin, precision, depth, variety and you couldn't rob him of time either.
Bottom line is that for a highlight reel, Gonzo's forehand stacks up to anyone's(even though I prefer Fed for the aesthetics and variety) but in terms of being an actual weapon point to point and match to match, it isn't in the same league as Fed's, who could dictate a rally with his forehand from nearly any position. In fact, besides Nadal's claycourt forehand I don't think anyone's forehand is really in the same league as Fed's. That's how incredible it was from 04-06. (03 TMC to 07 AO to be technical).
Take a match like the 06 Davis cup match against Djoker. Federer wasn't really going for anything on his forehand that match, mostly toying with young Djokovic to teach him a lesson and still you look at the complete dominance he was able to exert with the variety and angles he could produce in that match. Same thing with the 06 USO final, not a match Federer was trying to dictate with his forehand, but still complete dominance off that wing. And when Fed actually tries to dominate with his forehand there's really nothing like it. 04 USO final being the foremost example but there are tons and tons of other performances too that are just breathtaking off the forehand wing.