I would say it doesn't compare very well... If you look at the specs, Onkyo like every other HTIB company who is really an electronics company not a speaker company really distorts the specs to make it sound more appealing.... The thing with the THX system is that for a speaker to be able to be THX certified it must reach at least 20khz @ -6db and the sub must reach down to at least 20hz @ -6db so for a $700 all in one 7.1 system to be able to do that its pretty amazing.
Another way to look at this is you have a very nice TV; how much did you spend on it? Most ppl say spend at least as much on sound as you did for video. And basically how my system turned out is, the TV, TV stand, Blu-Ray Player, and A/V Receiver equals the price of my 7 speakers and 2 subs. And FYI I have a 2011 LG 60" PZ750 THX 3D Plasma TV.