I have used D2's and D4's quite a bit for toms, and was very impressed with the results every time. I'll be buying the DP5a set in the next few weeks, which has an i5, 22's, a D4 and a D6 as well as clips - seems like a good deal to me.
I personaly compared shure beta 98, 52 (for kick) and sm57 (for snare) with Audix i5 (for snare), D6, D2 & D4. What can I say? Audix are MUCH better for me.