[jkachmar]

Assuming the digital copies had an adequate bitrate, it's possible that the differences you're hearing between vinyl and digital are attributable to 'loudness war' brick-wall limiting. Some studios choose to use different masters for vinyl and digital which can make vinyl sound better.

To quote Daniel Rutter: "[B]etter-mastered music will sound better on cassette than badly-mastered music would at a zillion bits per second."

[1] http://en.wikipedia.org/wiki/Loudness_war

[tigeba]

This really isn't even a 'choice', it is practically a requirement for the medium. Some examples:

The outer grooves have relatively more fidelity (needle moving faster) than the inner grooves, so the master may be progressively tweaked to add more high end as the content gets closer to the inner groove. The closer you get to the inner groove, the lower the playback fidelity.

12" Singles have larger groove spacing so you can slam them way harder than an LP. There is a greater margin of error and less chance of the cutting lathe skipping or hopping during cutting the master.

The process for creating stereo vinyl recordings is pretty much a compromise that allows stereo content while maintaining compatibility with mono playback equipment. This results in another series of compromises/limitations in the mix, like severely limiting the amount of truly stereo content. Extremely loud or bass heavy content that is panned wide would cause the cutting lathe to skip, etc.