The cobra usb allows ps1 backups to be played, but you'll have to wait until they find a work around for your firmware. I think people got scared by the whole gehot thing.
If you can jtag your 360, i'd say go for it. Once you set it up it works great. It's nice to have all your games launch from one menu.
I've just found out about the everdrive, do you lose anything in terms of game quality when using that? I imagine it works pretty good, I do like having individual carts.. but that's just me.