Hi, to chuck a few extra opinions in, think Mr_S has covered most of the technical issues..... In a word "Forget it" !!!! (ok was two
Can't see either SACD or DVD-Audio will offer you anything. They are both intended as High(er) quality formats. But as you are happy to use compressed audio from a PC, any improvement will be pointless, the rest of the system needs to be cracking to get the most out of them..... Then they don't always sound better than CD, depends on how well it was recorded, mixed and mastered.
A universal machine would be the way to go, if you chose to, Perhaps something from Denon, plays everything around £300 -500 I would say, less than that as Mr_S said they sound pants !! ( I had a 575 as well).
Not aware of any PC drive that will read either HQ format. (Thinks it's to prevent someone cracking/copying them) Though I thought Sound Blasters support the 24bit 192Khz max rate of the DVD-A PCM system....so may be
NOTE, many/most SACD's are Hybrid discs, dual layer, so that they will also play on a normal CD player.
DVD-A are not, unless they are the new "Dual disc", which are thicker and can bugger up your player !!! AVOID !!!!
BUT the biggest reason is they are will be obsolete soon.... Sony is not releasing any more SACD, (It's their system) and DVD-A I guess will go the same way..... they are a flop and a failure....due to total crap marketing !!!!
I have a "Universal Player" and some of each disc........ Lucky it sounds stunning on CD !!