Hallman Pro has worked great for me.

 

I have a hallman and a Joe P., both are very realiable but recently I was on a road course for an extended amount of time in the summer heat the the hallman failed on me, causing my boost to spike to 28+ psi in the mid range RPM. Luckly I had spiked the tank with race gas and my tuning is conservative so there was no damage done.

I took the hallman apart a little while ago and it seems to be working fine again with the exception now having a very narrow range of adjustment, where before it was a much wider range. I'm going to try putting the Joe P. MBC back on before I hit the track again. I think the fact that its (Joe P.) an all metal (brass actually) construction it won't have a failure due to heat like the hallman which has plastics in it did.

 

im getting the hallman