I think any spin training is good, but for CFI's, I know some are being done a great disservice.
The place where I got my CFI gave us the option of doing spin training with them or doing it somewhere else. Their spin training consisted of going up in a C152 and doing 2 or 3 spins in each direction, and that's about it. In a C152. I don't know about you guys, but for me it always required a little bit of work to keep that plane in a spin.
I did my spin training for my CFI at an aerobatics school. Total cost of the lesson was maybe $50 more than what it would have cost at my school, but it was done with a competition aerobatics pilot in a Great Lakes. In addition to the plain ol' spin, we did some flat spins and accelerated spins. He showed me how different control inputs affected how flat or how fast the spin occurred and basically allowed me to "play" with each maneuver. In my opinion, much better training than what my "academy" offered.
Once we got to the point where I was teaching him the maneuvers for all three spins, he gave me the added bonus of some basic aerobatics - loops, rolls, hammerheads, etc.
I recommend spin training for everyone, but for CFIs, I think the training I got was the minimum standard for a spin endorsement.