Guys....your mid pipe isnt going to give you any kind of gains that you're going to feel, so if i were you i'd just go with the sound you like best.
As a rule of thumb, X is going to give you a big more HP in your top end, where as the H is going to give you more low end torque. As far as the Prochamber goes, if you've ever seen the cross section of one, it's basically a really wide and hollow X inside, so if anything it's going to give you similar gains as an X pipe, with possibly even more higher end HP since it's going to be even less restrictive than a regular X. I can tell you, any gains you think you feel are going to be purely "butt dyno" gains, reguardless of what 5.0 and MMFF tell you.
As far as which sounds best, it's pretty much what you like. The X is going to be a lot more "rippy/raspy" sounding, and the H is going to be a lot more "burbly/rumbly" sounding, kinda like a typical
Flowmaster setup. The Prochamber is kinda like a combination of the 2.....at low RPM is has the rumble/burble of an H, but once you get past about 3k RPM, it opens up and screams.
I'm never running anything but a Prochamber after having one...so that's my vote.
