This one will be quick. I used the Onkyo TX-SR707 as a processor. Feeding an external Innersound ESL amplifier for the fronts, Focal Profile 908s or something like that. To upgrade and make some dough, I sold the ESL, and the Onkyo, replacing it with an Emotiva UMC-1 and a pair of Yamaha P2xxx series amplifiers from the late 80s.
I had almost no reliability issues with the Onkyo. It functioned like a champ, and the universal remote that came with it was incredibly full functioned, though lacked meaningful backlighting. However, there is absolutely no comparison in the quality of sound between it and the Emotiva UMC-1 that just replaced it.
This isn't subtle only an audiophile would hear it either. It was a night and day difference in imaging and mid-treble to treble response. It makes me wonder if the Audyssey EQ in the Onkyo was totally off, or if whether there was just a generally depressed treble in the Onkyo. The Emotiva not only brought treble and sibilance alive, but filled in the images between my speakers. Honestly, I wish I had the patience and test tools because the difference is so great I can't believe these two units reproduce sounds above 4K with the same response curves. It's just a completely different world. I regret it took me as long as it did to upgrade.