Marantz is Denon's upline brand (a la Lexus from a Toyota). They're great and I use one myself.
Otherwise, it really comes down to room correction. If you don't need the room correction functionality, Pioneer and Yamaha make great receivers quality wise - their room correction is just mediocre.
Hi Ramyt and welcome to HTF!
I would seriously look at KEF in-ceiling speakers. I evaluated nearly everything out there when putting Atmos into my theater, and went with the KEF CI series - which are truly impressive.
Receiver wise, Denon is a solid bet. They have excellent Airplay and...