I have a Virus B, Octatrack and Analog Four. Between Octrack’s sampling and drum/percussion sounds from both the Virus B and A4, I don’t ever feel I need a drum machine.

It sounds like you haven’t clicked with the A4 yet. I too wasn’t very impressed with the A4 when I first got it but after getting a patch editor and really spending time creating my own sounds with it, I think it’s a great kit.