My reaction to GURPS: I like it. I like it a lot.
My biggest challenge with GURPS is gaining an intuitive feel for the game so that I can make tactical decisions on the fly. There are a lot of tactical options for players, both in combat and in non-combat situations. While the game mechanics are incredibly simple and consistent, there are layers and layers of moving parts to master in order to make tactical decisions on the fly during game sessions. These layers are a big part of why I like GURPS, but they do create a steeper learning curve than your average rules-lite games.
Oddly enough, I think that part of my struggle to develop a feel for GURPS comes from using Fantasy Grounds and the GURPS Character Assistant 4. Both of these pieces of software speed up character creation and game play. At the same time, I think there is the unintended consequence of new players skipping the grunt work is that the grunt work forces players to learn the nuts and bolts of the system. It is much learn like learning mathematics. Most of us have to us paper and pencil before we have an intuitive feel for how math works. Then you can use a calculator or computer to do the basic computations. But without the paper and pencil work,
I am at a point where I am starting to get how GURPS works at the tactical level. Besides the actual playing of the game, two things have moved me forward in wrapping my mind around GURPS. The first is that I like GURPS enough to have purchased (and read) several GURPS books—no small thing, given that I don’t buy a lot of RPG products (kids in college).
The second thing that has helped has been to create some cheat sheets for myself, using GURPS Lite. Rob gave me this idea by giving our group a one-page cheat sheet with offensive and defensive combat options. This was a tremendous help. I am in the process of creating a few more cheat sheets. There is a lot of learning that happens just just by creating the cheat sheets.
That all may seem like a lot of effort, especially after playing SW and AD&D 1e. But, given that I really like GURPS, it has been worth the effort.