It's generally a pretty safe bet that, if you want or need a receiver with the latest and greatest in AV connectivity, you're more likely to find it closer to the upper end of a company's product range than at the entry level. At least at first. But oddly, with the introduction of HDMI 2.0 (the new spec that allows for 60-frame-per-second Ultra HD, ultra-wide 21:9 video, and much higher audio sample rates and channel counts...without the need for new cables, thank goodness), Onkyo has taken exactly the opposite approach. The company introduced the new port first in its budget-oriented AVRs, the $499 TX-NR535 and the $699 TX-NR636, with two higher-end models following shortly thereafter. As such, the two receivers have garnered no small amount of anticipatory talk amongst AV enthusiasts on the verge of their next receiver upgrade, with the 7.2-channel TX-NR636 hogging the bulk of the discussion.
If HDMI 2.0 were the only new feature of the TX-NR636, I still think it would make for an interesting receiver and worthy of all the talk. But, of course, it isn't. In addition to the new connectivity standard, the TX-NR636 also supports the next-generation HDCP 2.2 copy-protection scheme, which gives it a bit of future-proofing. But only a bit, since HDCP 2.2 is only supported on one HDMI input port. (If you're curious, it's the one labeled "STB/DVR," which may give some indication as to which source components Onkyo predicts will likely embrace the more advanced copy-protection system first.)