I own the Buzzz in Pro D, Elite X, Elite Z, Glow Z, and ESP. Thoughts:
Pro D: I have never liked this plastic for anything other than putters. No good for the Buzzz. One taco shot and you're done. I never use this disc, as it was beat all to hell after about 3 weeks of use.
Elite X: Good, long, stable flight. Relatively easy to turn over compared to the other Buzzz options, but still takes the power very well. Nice an' grippy.
Elite Z: Generally more overstable than the X or ESP Buzzz's, these discs have a very reliable late fade. They are pretty slick, especially if it is cold out. They bounce with impressive recoil if you strike a tree, which can send you quite significantly of course. Can take a ton of punishment like all Z discs.
Glow Z: More overstable than the regular Z Buzzz, and also significantly more flat on the top. It is mostly just like the regular Z, but I really have to crank this one if I want to turn it over. Mostly I use this for long, gentle hyzers.
ESP: Stable to overstable, this disc has a bit more dome on the top. I love this disc because it is nearly as durable as the Z plastic with decent grip and it is easier for me to fly it a bit understable if I need to. It has a high tree-bounce factor, which is my only gripe. This is the meat of my game.
I have only seen and held an FLX Buzzz, so I don't have much to say about it. BCR commented that that the floppiness of the FLX nearly eliminates tree-pinball, so it might be worth trying out.
All of my Buzzz discs are marked 172 gram, so the weight shouldn't be much of a factor in my analysis above.