As i occasionaly DJ, i still keep an interest and buy vynils. Also, as have been mentioned before, lots of great stuff and limited releases only get pressed on vynil (the Deepchord label Echospace comes to my mind this instant). My take on the subject is that lots of ambient music where sound quality is a must (except maybe the more noisier, edgier or experimental stuff where the cracks and pops of vynils can add to the listening experience or is intended) could lose out on a vynil. Surely, some Steve Roach for example, would be wasted on vynil. On the other hand, music like that of Basic Channel (again, quick example), or Yagya as Undershadow may have discovered are definetly more vynil material and to my ears sounds a lot better, warmer and livelier than cd.
My point and experience being, that in general, the more dynamic and minimal music has a better chance to translate well on a vynil. 12" inches pressed loudly at 45" RPM with wide grooves are the best sounding. When too much music is packed on a side, the grooves will tend to get tighter and as a result, the dymanic and punch suffer ( Also, you're more likely to hear the scratches and cracks). In general vynils sounds better when you have no more than 10 minutes of music by sides for a 12inches 45" RPM (15 minutes for 33 1/3 RPM). Often, when you listen to older LP recordings on vynil, where they used to force more than 20 minutes on the side, the music sounds so tiny. That's why now, Lp are often pressed on 3 or sometimes 4 vynils, with 2 or 3 tracks by sides.
Also, it is good to known that the sound quality is best at the edge and decreases as you get nearer the centre. It's especially the high frequencies that tend to suffer most..
Vynils need a special mastering, that differ from cd. For example, the stereo imaging should be a bit less wide than on a cd.
I am not working at a vynil pressing plant, but my experience as a buyer, and for having had one 12" pressed in the past has taught me some valuables lessons as to what, to my ears at least, and in the more electronic type of music could make a good vynil and the best listening experience you can have with them and as result it does influences the music i rather have on a cd or vynils.
And if you want to press your music on a vynil, it can help to known those little details as it may influence your creative decision for your pieces you'd like to see spinning on the black, coloured, or transparent slice.