I've got a Roland TD 30 and I don't have machine gunning with that, but before that I had a TD 9 and that really did machine gun. But I also use addictive drums samples and there's no machine-gunning with that. By the way I think the TD 30 does trigger the samples a little more accurately. I got a nice set of Sonar which tunes up real nice but the problem was always getting the sound out to the people and there was always microphone bleeding which of course electronics just doesn't have.
I want to say this about the TD 30, that it seems to be more dynamic than the samples and the sounds really are very good, not as good as samples but they're more dynamic. I usually use only three maybe four different drum kits but I like having the option of different sounds and percussion. It really did take me quite a while to get comfortable with the transition and the different sensitivity of the drums and cymbals, but the TD 30 often does make me feel like I'm playing an acoustic kit.
Anyway, to each his own both have their own strengths and weaknesses. I think one thing that hurts electronic kits is getting the dispersion, dynamics and frequency response on stage. But it seems more more bands are going in ears and so that's less of a problem. Anyway that's my two cents.
http://www.youtube.com/watch?v=7n8ndXWytyw