I have two of the Fulcrum "Ultimate" kits and two of Zev's Standard "Ultimate" kits (Production/SSP legal). They are all VERY nice triggers.
As for how much pre/post travel you can adjust out of them... If you have the time and the patience, you can pretty much adjust it ALL out. I mention time and patience because you have to remove the trigger block every time you adjust it, so it would be a LOT of disassembling and reassembling to get it dialed-in that tight. Personally, I did a bunch of adjusting on the first one I bought, but I'm shooting the other three just like they came out of the package. It's already adjusted pretty well by default.
Compared to a stock trigger (I still have plenty of Glocks with close-to-factory triggers), I don't notice any mushiness. Everyone who has shot one of mine has commented on how good the trigger feels. Even some of those "Glock triggers are perfect out of the box" type guys. I run the factory striker springs. I don't have a trigger pull gauge, but I'd say they are pretty firmly in the 4.5# range based on my experience.
I have another Gen 4 G19 showing up tomorrow, and I'm probably going to put another Zev Standard trigger (drop-in this time, using the factory striker and spring) in it. I like them a lot. I think they're worth the money.