The reviews are out there for the 970. Stupid good for the money, fantasic when a DAC is added.
Ric Schultz (tweakaudio.com) and RAM (referenceaudiomods.com) offers a variety of modification options ranging from $200 to $1415 (which void the warrantee). Not sure if spending more on mods than on any stock piece makes tons of sense though. And frankly the Oppo doesn't strike me as well built enough to even want to put much money into a DAC let alone mods for it.
Like everything thing else it must be measured in terms of cost and your budget. If you are planning on a $5000 system, the stock Oppo is probably a poor match. If you're comparing it to $1000 digital options, again it won't hold up well against the currently best available. Below $1000 the stock or Ric Schultz modded Oppo may be the best sounding player options currently out there.
And like everything digital, time marches on so expect that next season a new darling will be introduced. And that new darling will probably be cheaper too. Makes you wonder why anyone should heavily invest in any digital source.
I'm using a stock 970 in my $3000+ system while saving for and researching what to do next. Can't say that I'm completely satisfied with it in this system, but I'm not "suffering" much either, and figured it'd be plenty good enough down the road for the TV in the bedroom.
If you look through Audiogon, you'll find hundreds of guys losing hundreds on CDPs that are 0 - 2 years old. Compared to that, how can you lose with a $160 (with shipping) universal player that provides good stereo sound?
Of course the digital music server options exist at all price ranges with varying degrees of sound quality and convenience. This is the future of digital sourcing, if you're ready.