Best way to quantize midi drums?

Best way is the hard way: by hand, one hit at a time. Try to determine which "off" hits were the hardware's fault and which ones are natural human imprecision - and do your best to keep the latter intact.

I have used the quantize feature with success.....

I think you select the track and highlight it..... select the Quantize function. In the window that opens you can set the parameters you want... resolution of the notes... percentage dead on and so forth....

I used this on a piano part I played manually. I selected the 16th note resolution and told it to get the notes 100% dead on the beat.  It did the whole song in about 2 seconds..... I thought it worked well.  I ended up deleting the track but the Quantize works well on any MIDI date.

You can always use the undo function in EDIT if you don't like it.

Guitarhacker...I don't think you can fix a song full of double kick firing  with just tweaking the quantise automation (unless it's a relatively slow-tempo song, which seldom is the case when you talk about double kicks)!
The beats are most likely so close to eachother that any automatic editing throws them here and there.
Shooting something like 32's or 64's in a high tempo means there's inevitably notes that are more than 50% off.

I agree with Bitflipper - you need to do it manually.