I got my EZV-3-in-1 first, and I was a little unsatisfied with it, since you have to use NOR for large ROMs (SLOW), it looks a little ugly (doesn't sit flush), and it only provides 16MB of RAM for homebrew. When I got it, I wished they'd just put in 32MB of RAM, which would have been cheaper and faster in the long run than 16MB of RAM + 32MB of NOR Flash.
So as soon as I heard about the Ewin, I got one. I still like it more, and am pushing for it anywhere I can (in the hopes that more people buy one, and in turn it gets more attention from homebrew developers). It fits perfectly flush, provides 32MB of RAM, and loads games even faster than the EZ-Flash does in PSRAM mode. Now pretty much all I have to hope for is that somebody makes a better GBA Loader (the present loader has problems with certain savetypes) and that somebody adapts kzat3's hack for the Japanese NDS Browser to the EU version.
In my own case, I only use the Japanese browser, so that recent hack was a godsend. Also, I own every game that I play on the Ewin, and I just copied the saves from my carts and put the ones that weren't working (all tiny saves that are mostly just unlocked features) on my R4 as read-only files, so I can do everything I want to on the Ewin.
So I recommend the Ewin, but I also realize that I'm in the minority, and will probably stay there, just due to the sheer number of 3-in-1s that have sold already (EZ-Flash had a BIG head start). Forget about the rumble when you make your decision though; the 3-in-1's rumble feature is terrible, and you're better off getting an Ewin Rumble Pak or the official Nintendo rumble pack.
