The T67M mkII that I fly has an aerobatic capability about the same as the Bulldog, perhaps a little better. Not quite as nice to fly as a Bulldog though, and less powerful, so slower to climb etc. Better instrumentation, no fatigue meter and an average fuel burn of around 30 ltrs per hour swing the choice toward the T67M for me.
The T67C is less capable since it has no inverted systems. With a free choice, I would choose the Bulldog. However, if the Bulldog has a high fatigue index it will deter you from finding the outer edges of the envelope. I know of one Bulldog used by a school in the south where the instructors are limited to 3 1/2 g maximum. This allows Sunday afternoon aeros to be taught, but is quite restrictive. The firefly is a robust airframe and there are no fatigue issues.