I like it. Seems to spool up well and easily gets to 15-20 psi. Not sure if it would go higher with wastegate adjustment or not (set as the stock cummins setting, which IIRC is about 18 psi). My setup is a fully custom mount/piping and while it fits well there, I think you'd have clearance issues on a standard aftermarket turbo mount/up-pipe.
That being said, there's seem to be a lot of people who will claim it's a bad choice, however I think that's all based on folks who think they're book smart and haven't actually used on. My $0.02, it's a good setup. I have no EGT issues and feel like it gave about 50% power improvement over a Banks WG setup. Never run on a dyno, but I can do 55-65 on a 4-5% grade at ~15k gross and 40-45 on a 5-6% at ~20k gross. That's with a Typ4 cam, ~0.015" decked & ceramic coated pistons & studs but otherwise stock 6.9. Had to pull the engine at about 75k due to a cracked piston (plugged oil jet, probably shortly after the rebuild) and the internals were all in good shape.
Probably is a build thread somewhere on here, but not sure where.