I have one White Diamond that I have yet to try out. I know a few players who use them and are quite happy.
I mainly install Mad Man jump/break tips. Juan sells them in the Machinery Forum and are very reasonably priced. I just looked at a guys breaker that I installed one on over a year ago. You would never know that it was that old.
A 25 oz breaker. You pick it up and feel that you have to be a Knight in Shining Armor to wield that thing.
Anyway, these tips are about as hard as phenolic, yet leather and they have a bit of control to them. I have installed quite a few on jump cues. Seem to work well and have had no one complain that they can't jump with them.
Myself and quite a few others, I have installed Super Pro. They last almost forever, very hard, and I feel that you have a serious amount of control with them.
There are players using them that have had them on for over 2 years now. I'm pushing close to the 2 year mark with one on my Joss Hammer. Still almost new. And I play a lot of pool. Its is also the teams community breaker most nights. It gets much use. Very reasonably priced. I believe you can still buy an entire box for under $20. I have a life time supply.
Myself, when I first got a breaker with a phenolic tip, I thought it was the best thing since sliced bread. That is until I put on a Super Pro. I would never go back to phenolic.
You know what they say. So many tips, so little time.