Originally Posted by LastSensei

Registration in DMM is a little hassle. You need install and configure some stuffs so that you wouldn't be blocked by its region restriction.

Hmmm, first time hearing about this.
I've checked out the DMM version out of curiosity and had no problems with the registration.
Maybe it needs japanese fonts/regional settings which I had by default since I'm using the language.

About the difference - you've already gotten a good answer. Basically a lot of goodies are available on DMM which I hope that will appear on this version the sooner the better. For example, a separate backpack with 200 slots where you can move your upgrade materials, or the existance of manyuus for equipment. Not to mention many different scenarios to play.