I'd vote for digital. I just brought Dr. Beat into the darkroom, and am more accurate than my Gralab 300. Setting small intervals for test strips had quite a bit of variance, but we never really printed anything less than 10 seconds. With Dr. Beat, I can set sixteenths @ 120 BPM and get 1/32 second intervals, with quiet good accuracy.
However, I have been playing bass for over a decade (mostly jazz) and have been noted for having excellent time and groove. My girlfriend is a drummer, so she's definitely not a slouch with beat/groove either. YMMV depending on your musical skill, though. For us, at least, we've been overall happier just manually hitting the switch on our voltage regulator and using a metronome vs the old GraLab 300, so if were going to buy one again, it would be a digital one.