I read up on both, and from what ive heard they are close. One thing Ive noticed though is that Ive heard about more slow down in games on m3 simply if u dont buy the right or a legit memory stick. The r4 however, ive heard of 0 slow down.
The M3 and R4 are identical, they both will suffer from the same slow-down if using a crap card. The M3 just gets more attention, therefore more reports of problems when things go wrong.
The only main differences are:
R4 gets updates about 1-2 days before the M3
R4 case is white, M3 is black/grey
If you are really having troubles choosing, get a picture of each device on your screen and randomly point at one, then buy it :-)
Thanks guys im going with the R4 but im still torn on where to buy from. I went to the buyers guide but... I just want a reply to anyone who ordered from a website with really fast shipping, or sdecent shipping options for the r4. I prefer and r4 bundle with 1 gb kingston. any help?