I’ve just been demoing groove-agent 4 and ez drummer 2. I like them both. Groove agent 4 is a much deeper program. But I think that it’s great when you understand how to use it.
I also think that it sounds better than EZ-drummer 2. I tried a lot of different settings on both of them, and every time I preferred the sound of groove agent 4.
So sound vise it’s a good product. At least to me.