I just did mine about a month ago, (along with a complete suspension upgrade), I used Bergman's kit.
It was really an easy swap, with excellent results.
I would say that, too me, it feels like it's too much "boost". From perusing the web, other's have felt the same. But, there's a relatively easy fix to lower the pump pressure. All you need to do is shim the pressure regulating piston.
It is my understanding that the "std." V8 Saginaw pump puts out 1200-1400psi. The Borgeson seems to have better feel if lowered to it's "design pressure", in 800-900psi range.
I'll be doing this mod in the not too distant future. But, as is, the Bergman/Borgeson is still a huge improvement over stock, or FirmFeel.