I can't comment on oppo, but on the subject of failsafe CD labels, then the following would fall in that category, IMHO.
Stockfisch, A great German label, with some wonderful artists, Sara K, David Munyon, Alan Taylor and many more.
ECM, recordings are faultless, but the music can be a little avantgarde, shall we sat. Start with one or two of their compilation CDs
Chesky, of course, as suggested above.
For classical, Hyperion and Chandos are hard to beat.
MOFI
Dali: The speaker company, produce some astonishing compilation CDs.
Linn and Naim, two UK HiFi manufacturers that have been releasing great Cds for years.
There are many more, but that should get you started.