Keep in mind that most replies you get, including this one, won't be from "experts". I did, however, take the time to look up the 2 receivers you listed. From a quick glance, it looks like the Onkyo has no per-channel equlization, while the Pioneer does. If you're planning to build an acoustically perfect room for your new HT, then this feature won't make much difference. If you're planning on using your equipment in an existing room, it could make a big difference.
My advice is to get a Denon like someone else recomended. Buy the Pioneer that has equilazation and send it to me. I'll send you my Denon that doesn't.