Fire Red was annoying. I faced the first round with Pokemon in the low 40's, and it wasn't that bad at all. The second round sucked, though. My Pokemon were in the 50's. It didn't help that I found the game to be boring, so I didn't really have the patience to train anyway. It also doesn't help that I don't have anything effective against Gary's Alakazam...
Sapphire was ridiculously easy, especially Steven, since I had a Blaziken that completed destroyed his team. Never tried Emerald's Elite Four, but I'll assume it's a little harder because I can't beast it with my starter, and I can't think of any Electric types I'd want to use off the top of my head.