All the theaters in the Loews near me are digitally projected. Sound was pretty good...not surround though for some reason. The picture is why I like digital showings, just the higher resolution and less artifacts and fewer focusing issues usually (well, maybe not an equipment issue but an employee issue).
As for sound. All sound is analog. There is no such thing as digital sound. The signal that hits your speakers or headphones is analog. Always. No exceptions. That's how speakers work, with an analog signal. This means if you're seeing a film whose audio is stored digitally, like most probably are these days, they're run through the theater's DAC (Digital to Analog Converter) and through amps and other equipment they have. The quality of the DAC will vary, but any decent theater should have some pretty top notch gear.
My point is that if sound is better in a digital theater, it's just because the sound equipment is better, not because it's "ooh digital, fancy".
Bassoon, n. A brazen instrument into which a fool blows out his brains.