it is that there IS a difference between the cards that matters... yes, they all do work, which is why when i got an M3 Real, i was so excited/happy i wanted to tell everyone to get one... it was my first, and i hadnt tried another card... then i tried an R4, and wow, it was faster, and could hold and swap between 12 skins! the M3 only could utilize 4 skins... and after skinning for it, found that the limited memory for the skins on the card meant if i went wild making a NICE skin, it could not handle it and froze up and crap... not to mention with the skins i did make, being so nice, they slowed down the card massively... R4 didnt have that problem, and could still do everything the M3 did... so i tried an Edge card... and it is even faster, cleaner, uses cycloDS skins, holds 30 skins! and does everything the R4/M3 does, but even cleaner/faster with a great update team to fix any problems since it is new... it handles HC cards, and again is better than anything the R4/M3 team has out... the TT seems to be an R4 replacement that uses HC cards... nothing really new otherwise...
so yes you could buy any card, and am sure you would LOVE it, unless you actually try something better, which is why people, including me, try these things out to let peeps know the ins/outs of each one... if i knew now what i didnt know then, i wouldnt have bothered with either the M3 or the R4, but would have tried the Edge, Cyclo, and the Supercard... y not get the best you can for ur $?