Hello JCMO...I am new to this Home Theater stuff too and have been driving myself nuts on what receiver to get too. I've been reading about the 707 and also considered the Pioneer Elite 23THX. After several weeks of research and reading these threads, I just ordered the Elite. Still not sure if that is a good move or not, but I have 30-days to return it once it arrives.
From what I've read, they are both very good receivers. From a sound quality standpoint, I understand that the Onkyo has smooth sound to it and a bit bassier sound, while the Elite is much clearer and precise sounding, whatever all of that means.
Both, from what I've read have their share of issues when it comes to the video portion of things, but I do not know enough to make any intelligent comments on that.
My opinion was...The Onkyo has more issues than the Pioneer and that he Elite amps inside were a bit better. But again, everyone has a different opinion and many on here, not all though, have their favorite Receiver brand, just like people have their favorite brand of car, appliances and other things. Not sure if you will ever get the answer you want. I think you just have to take what you read on here as valuable advise, then, try to listen to them both and determine for what you will use it for, what receiver has the better options and least amount of problems.