First off let me say that I found this forum 10 or so years ago when I was having audio sync issues between my old Denon (don't remember the model) and my new Samsung flat screen TV. Based on information found here, I think specifically from Batpig since I found an old link to his site, I ended up upgrading to what is my current Denon and fixing the sync issue with a manual delay configuration.
All that to say, it's great that this is still going and helping people out after so many years
On to my issue -- forgive my rambling
I was lucky enough to get a good deal on a full 5.1 set of Klipsh reference speakers from the Black Friday sales this year -- replacing my 20 or so year old Pioneers and used up subwoofer (old velodyne from a friend that was never real robust). Unfortunately, my aforementioned 10 year old, Denon AVR-2310CI decided to pick this time for the subwoofer out to quit. The cable was very tight, but the RCA plug doesn't move, so I think it had something go out. I had trouble getting it to work originally with the new sub, but wrote it up to the old tight cable because when I replaced it with a crappy RCA video cable I had laying around it worked. At the time I didn't hook up my surround speakers because I was running new cabling so I bought a new subwoofer cable and it didn't work again after changing it out (even on the cable that worked before or the original sub cable). I tried the 'running a finger over the tip of the cable' trick that jdsmoothie posted (thanks for that) and I get sub noise so it's still ok, but I get no output from the test tones.
So, 10 year old receiver - I figure it's time anyway.
I know that ultimately I'll probably be in a good place with any of the choices, but I've gone through all 49 pages of this post, but I'm still unsure so I'd like some opinions.
I've never really been unhappy with the AVR-2310CI, and if I'm reading the spreadsheet right that dfa973 posted, the 2310CI is more comparable to the X4500H line - although I may be assigning too much value on the horizontal there
I have a crummy room setup, that I have to live with, so I'm stuck with 5.1 - my couch is against the wall, so I can't really even put in surround rears correctly --- my surrounds are on stands 90 degrees to the sides because wall mounting isn't an option.
Speakers - all Klipsh Reference - Front R-820F, Center R-34C, Surround R-51M, Subwoofer R-120SW
TV - Sony XBR-55X850C
DVR - Tivo Bolt VOX
BluRay - Sony BDP-S550 BlueRay player (probably the next upgrade)
Streamer - Roku Ultra
All 4k capable, except the BluRay player - I'm nowhere near 8k.
Given the room restrictions, the virtual height speakers are attractive but not required.
ARC/eARC isn't an issue since I control everything from a Harmony remote and I don't back-feed audio from the TV.
I don't currently use anything but the main zone.
I've never been wowed by Audyssey, but I will admit it did a much better job with my new speakers than it ever did with the old ones so I expect it's a function of what it has to work with lol. So I assume that Audyssey XT32 will really help out a lot with the room issues.
I'm leaning toward the AVR-X3600H, although truthfully it's bad timing because I would go for the AVR-X4700H if it was available. My new speakers produce a lot more bass than my old ones, but I don't think I want to wait 6+ months before I can use my sub. I don't really like the idea of buying something to just get by until the 4700 is out -- so whatever I get will likely get the expectation of long service like my old unit.
It looks like I have a multi-line display now, and although I probably don't need it I'm disappointed that the AVR-X3600H has a single line display.
AVR-X4500H (yeah I know not 2019 model but I'm so far behind now I don't think I can say I'm all that worried a lot about HDCP 2.3 and HDMI 2.1 right now-might be a mistake)
or drop out of the pro line with AVR-S950H