I was getting blown up very easily in the assault cruiser, far more so than in the base-model patrol escort, which just seemed wrong. It was more a case of having the right BOff skills I think, and struggling with the loss of turn rate. Doing less damage AND dying faster didn't make for a fun experience. Now I must admit that I didn't stick with it for very long. It also probably didn't help that my Tac captain is specced out with an escort in mind.
I have some cruiser oriented BOffs just waiting for a ship to fly, but they probably still need some adjustment. I've got the hang of escorts--if I chose another one I don't think it would be much of a challenge. The cruiser, though, would present some effort to master, and I'm leaning towards it for that reason.