Al salam alykom

I myself did a little research because en sha'a Allah ill transfer to Islamic banks.

I found that QIB (al masraf) is much better with customer service. Also it's the oldest Islamic bank in Qatar.

I didn't get much positive feedback on QIIB and my first impression was bad.

There is also Al Rayyan bank which is new but everyone seems to have something positive to say about it.

I found this to be true, Visit their websites and the impression you get from the website (to me) is exactly parallel to its real life impression.

Also need I remind you to be careful of "Islamic windows" in commerical banks.

Good luck.