I'm debating to buy this pump or not
I hear mix reviews about some being loud and some being quiet

If It's your return pump. I woudlnt skimp on it. I would go with an ehiem 1260.

I had the rio hyperflow 12 as my return for my 40br and there is nothing wrong with that pump. I never heard it in my stand and it never failed me. I would recomend this pump if your not looking to spend over 100 dollars on something that will get the job done just as good. I still have that pump lying around in my spare parts collection closet in case I decide to ever set up a larger tank again. It moved some water and my gsp would move all kinds of directions from the return alone making it hard to tell when my mp20 was off so that should tell you something about the power in that pump.

It's not going into a sump I was gonna use it for AIO 40 breeder
Running 2 returns
I'm debating between hyperflow12 or a maxijet 1800

I have these pumps in all my tanks and I have never had one die on me yet. They are also very quiet as long as the housing isn't rubbing up against something.