Isn't there something about compatibility issues with EZ (not necessarily EZ4)? Since if you are going to use them for DS applications you would be needing Passme/Passcard variant, and currently Superkeys/Passcard does not support EZ... Or EZ2 and EZ Flash II are different (kinda confused here, really...) [This is actually the reason why I am thinking of purchasing another flashcart (probably supercard) although I have EZ Flash II, since I read that it is currently not supported by superkey/passcard variants]
EZ2's and EZ Flash II's are the same thing, yes. EZ Flash and EZ Flash Advance are different products, though.
The EZ2 uses a different loader then the EZ4, I don't know if it's compatiible w/ Passcards or not, I don't have a Passcard of any sort to test it. So if it isn't, until EZ Flash release their own Passcard-type-thing (should be soon-ish FWIU) your options are using a Passme 1/2 and/or Flashme'ing your DS. I think EZ Flash has given up on making sure EZ carts work w/ the Passcard. They fixed the EZ4 3 times so that it would work w/ the Passcard/Superkey, everytime the very next version of the Passcard/Superkey did not work w/ the EZ4.
If one isn't hung up on a passcard style passme, it just seems like a very nice alternative to the current "hot" products. I mean, when compared to a G6 (the closest competitor, IMO), you'd loose the "crystal engine" movie player and have only slightly lower DS compatability and save $50 (at Jandaman's shop anyway I didn't look very hard).