I have tried ALL of the rigs in your poll, so here's my two bits.
Wee/Wa: Best option available if you want to carry a LOT of ammo, but I didn't like the built-in mag pouches. Mags are tight when there's 2 in each pouch, but loose as a goose when you remove one. Also didn't like the way the whole rig gets looser as you remove mags.
Eagle PC w/cummerbund: By far the most comfortable of them all, but also the most trouble to get in and out of. Offers a lot of real estate for attaching pouches. One drawback for me is that if I use the Sm/Med, the plate carrier fits me and my 10x12 plates beautifully, but the cummerbund is way too short. If I move up to the L/XL, the cummerbund is perfect, but then my plates have too much room to slide around inside the carrier. Plates are pretty secure after everything is cinched up, but usually need to be manually recentered in the front plate carrier before securing the cummerbund.
Woo "A" and "E": I like these the best because they are so FAST to get in and out of. Use the "A" version if you need a lot of real estate. I like the "E" version, as it's easier to reach the side buckle when putting it on, and there's just enough real estate for me to attach one Paraclete ATX triple mag pouch and one "double-double" M4 mag pouch. Gives me 7 M4 mags and 3 pistol mags in a relatively compact, secure rig that's very fast and easy to put on. (edit: Just received another Woo. Let's just say that quality on this one is not on a par with my older one... I'm swapping it for another Eagle.)
Another drawback to the Wee/Wa/Woo's is that they sag a lot with no plates in the rig. The Eagle PC w/cummerbund can be worn just fine with or without armor.
eta: One other thing that I've never seen anybody else mention - the shoulder strap location is a bit different between the HSGI rigs and the Eagle. The Eagle put the straps closer to the centerline of your body, which I like. May not matter to you, but it was something I noticed immediately when I put it on, after having tried all those HSGI carriers.