I also like the Yamaha HS 5/7/8. I just installed a pair of HS7s yesterday. I didn’t audition them against other contenders. I didn’t try them out in my room beforehand. I did none of the things they say you should do. (I think VinnieD’s advice is correct.) But I really couldn’t be bothered, and I don’t trust my ears on this issue anyway. (I have just about zero experience evaluating monitors.) Instead, I did months of research, read and listened to many reviews, compared spec sheets, looked into the reputations, and so on. In the end, I was satisfied that the HS7 would deliver the most accurate sound.
In the real world, I find them very quiet, and they deliver fine detail. Playing Halion sounds via keyboard controller has been a superb experience, similar to headphones, but less claustrophobic. This is true at low volumes as well. (I control volume via software, not the volume knobs on the back of the monitors. They are set to +4, matching the output of my digital interface.)
Why HS7 and not HS5, or HS8? The HS5 doesn’t seem to have a full enough response. The HS8 is better than the HS7 on paper, but it wouldn’t be better in my room. The stronger low end would likely not work a room of my size. It would create acoustic problems of the worst sort (bass). A sub-woofer would make things even worse. But you have a nice big room!
Is your room acoustically treated yet? If not, then you have a chicken and egg problem. How can you compare monitors that’ll stand in a treated room that doesn’t exist (as yet) in treated form? How do you treat a room without knowing what monitors will go in there? Theoretically, it’s easier to treat the room first. Use any monitor at all, a reference mic, and software. Financially, it may be harder to do that. What if the treatments are ultimately inappropriate?
If your room is treated, and you trust your ears, then go audition competing monitors. But if your situation is similar to mine, then I’d say the HS8 is a safe bet. You may want the sub-wofer that comes with it as well. According to my strategy, the next steps would be to treat the room (guided by Room EQ Wizard), then calibrate the monitors at the mix position with sonarworks.