What is the difference between R4i, Acekard 2i and DSTWO

What is the difference between R4i, Acekard 2i and DSTWO?
Hi all!
Now that I know where to buy a flash card (thanks to some of you awesome ppl), I need help figuring out which one is the best one to buy.
I was originally going to buy an R4i but then a friend told me that the Acekard 2i is better.
Now, I really don't know the difference between any of these and I also don't know where to get the software for the Acekard 2i. So here I am! I appreciate any help, thanks heaps!

Answer :
They all do the same thing..but there's one big difference
R4i can only play about 80% of the games,
Acekard 2i can play about 99% of games

the difference is compatibility and acekard is just more compatible
and everything you need to know is right here :www.gameqo.com

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