I just bought a bunch of EZF Advance Carts (for friends and family for XMAS) at the advice of Jive3d and I freaking love it. I got a gold SP after Thanksgiving and I can't stop playing NES games on the GBA. It is cool beyond words.
I'm playing all the Megaman games, Zelda, Tecmo Superbowl, Bionic Commando, Bubble Bobble, SMB's, etc. I put approx 60 NES games on 256mb cart and it's only 1/4 full.
Hey, it's even a good way to meet people. I was sitting at the mall playing while waiting for someone and an attractive young lady walks by and can hear the sounds. She said, "Isn't that Zelda?" and off we went on a convo about retro gaming.
So, if you don't own one of these stop what you're doing and buy one now. You won't regret it.
PM me if you want info on where to get one in the US. I'm not selling them, nor do I profit in any way by passing on the info.
D