I have found that, on the whole, if you are using a drum machine for a live band or arranger drum section, if your live players have trouble keeping time (if they don't suck with a live drummer as well, that is ) it is usually due to how easy it is for them to 'swamp' the machine, which doesn't have a fraction of the dynamics of a real drummer, nor automatically gets louder when the rest of the band does...

Only solution I have found to this is to make sure that the drum section of your arranger goes to separate outputs (if your arranger has them) and to run them through their own dedicated monitor rig onstage if possible, or at least make them hotter in the band's monitors than the regular keyboard parts. And, if your arranger has a function where the ACC (especially the drum Part) gets louder or quieter depending on how hard you play, set that up so that, if you have to start banging a bit harder because the other guys start getting frisky, at least the drums will get frisky with them!

This, in my experience, has solved all timing problems with live players that I have experienced. If they can play well with a REAL drummer, all it takes is recreating the 'real drummer' experience for them... and if they can't play well even with a real drummer, what are you doing playing with them, anyway?