Well I've had some time to get a decent feel for my TX-RZ620 over the last week or two. I can say this for sure, no one will be shocked, that it is quite a bit better than my old Yamaha. For being the base line in the RZ series, I don't see how you could go wrong unless you need that extra little bit of extra power or better zone options. Initial impressions upon opening were how much AVR receivers have changed over the years. Comparing the inputs, the Onkyo seemed spartan compared to the Yamaha simply because the old Yamaha had so many Svideo, RCA, and component inputs which have now largely gone by the wayside for the masses. Once hooked up and having run the calibration, I set out to see how some familiar material sounded. I have to say, the bass management on the Onkyo was probably my biggest surprise, it made my BPS-400 sub feel like a new sub. After crossovers and such were set, I was able to reposition my sub to somewhere with better wife approval and still get better bass out of it than where it was (my living room is very bad for sound, basically a large rectangle that can't be put optimally no matter how you slice it). Mid's seemed to come to the party a bit more than before and that signature Onkyo sound quickly made a big fan out of me, every bit as good as I remember. I had a friend who has invested way more into audio than I probably ever will come by and give it an audition and he was impressed with it. Seeing as how he has separates and higher end speakers, I took his praises as a big compliment.
I will say this, at one point I had some orchestral material playing at moderate to high volume with the sub off (repositioning it) and at one point I had to stop and just sit down and enjoy the sound that this receiver made my speakers produce. The full, warm sound and SPL it was able to make my meager 5 1/2's drivers play (Mirage FRX-7) took me back to a simpler time when I first heard my Mirage mains and I honestly felt like a kid again, enthralled with what these speakers were able to reproduce in simple two channel stereo with no sub. Make no mistake, I know I have older midrange speakers but, and maybe I've been out of it too long, this receiver was able to make me go "wow" with it's clarity, power, and range it had.
I am very happy with my purchase and would recommend this series to anyone looking to upgrade. While the remote leaves something to be desired (as I've seen others mention), it is functional and gets the job done. The plastic volume knob is a bit of a downer but 99% of my listening is done via the remote so I don't get hands on with it very often. I will also note that the receiver seems to run cooler than I had expected given what I've asked of it while listening to it. Overall for me, for my application and use case, I'd give it a 9/10. Let's hope Onkyo's HDMI issues aren't present in this series and if not, I'm sure I'll get many, many years of enjoyment out this receiver.
Onkyo TX-RZ620 | Polk LSI-15 | Polk LSIC | Polk FXIA4 | SVS PB1000