I've been a long-time shopper from DX, and recently started shopping more from MF since they have a much better record for shipping more quickly. Unfortunately, on my last order from MF, they sent me the wrong item (I ordered a P60 dropin with a Red secondary emitter, but they accidentally shipped me the same dropin, only with the Blue secondary emitter). I have been working with their support staff for a couple of weeks now without satisfaction. Jim has assured me that this will be addressed, but I have not yet received confirmation that the correct drop-in I ordered has been shipped to replace the one I received. I have a second post here I'll be updating regarding this issue once I get an update.
I will add that recently, DX has done a much better job of getting orders shipped out for me, but they have been smaller orders of more common items (some LED drivers and 3D glasses). It seems to help when you make multiple small orders rather than one large order with different types of odd items.
I have never ordered from KD, but will eventually, since they have some good drivers and AR coated lenses I can't get from other sources.