I love my BOSS DR 770
! It's already outdated of course by BOSS' new drum machine but it's still second best in their line. I bought it as a display and traded in one of my old stomp pedals as part of the payment but I have never regreted it. It's sounds awesome! I have had several people that cannot tell the difference in my recordings as far as it being an actual drummer. You can program this thing down to whether or not you are hitting the cymbal towards the center (bell) or towards the outer edge to give it a more ringing tone. You can pan your drums adjust tone and there is a two band EQ build in. It also has effects like Chorus and Flange and there are Ambience presets as well to get a little more of a "live" sound out of it. If you would like to hear some samples of what I have done with it you can hear the songs on either one of these sites of mine.
And heres a link to some info on the drum machine:
This thing also has a ton of cool presets to use or you can write your own which I prefer to do.
Either way it never gets tired or starts complaining and it always does exactly what you want every time without having to throw in it's own 2 cents ") If you have the extra cash this is the way to go. I tried a few Alesis machines but they did not have the features I was looking for, they sounded a little too fake and the few I tried did not have the option to turn off quantization which gives you the "real drummer" feel that I enjoy. Hope this helps you a little bit.