i find it to be a very good combo! :D
you get the strong mdma feeling (what you are probably used to) then the mda starts to make everything look a little different, a bit like being on acid. it also makes me a bit more introspective, so i'll think about things a lot more and dwell on problems or ideas a lot more if i don't have something to keep myself entertained with.
expect to hallucinate depending on how much mda you have, the more you have the more likely you are to hallucinate. different people react differently to mda, like acid again, so you may not hallucinate at all.
if you drop the mix at the same time you will notice the mdma come on first then a little later the mda will smack you through a breakwall and you'll be up in the sky somewhere.
try and have some anti-oxidants before, during and after the roll. vitamin-c or multivitamins are usually good or try and have some citrus fruits the morning after. the reason for this being that it helps stop the damage on your brain. you should try and do this every time you roll but especially when on mda because it is more neurotoxic (causes more damage to your brain). if you want detail on how the anti-oxidants help your brain, check erowid and this forum. i'm sure theres plenty of info there, otherwise ask here.