I use EZDrummer and get great results. I had it for a couple of months until I just pushed eveything else I was using aside and made myself learn it. I'm very happy with it. Using Logic as my DAW, I am able to play in fill and fix or fine tune parts to get what I want. The bottom line is getting real sounding drum tracks.
I had the advantage of attending M.I. in the 80's and hung around all the great drummers. I learned what the finer points of what real drums should sound like as apposed to machines and sequencers.
I use my KB37 to input the MIDI data but I really need an electronic drum pad. With that, You can do anything.
I cand from using Drums on Demand for several years and I love them, but I need to set my own tempos to truly write songs. You can't always be confined to set loop tempos.
I wish that I could upload a song to show an example of what kind of results I'm getting.