I finally gave GURPS 4th edition a perusal, and I was really impressed. It looks like it fixes some of the bigger problems I had with 3rd edition. I am happy to see that point costs for HT and ST have been decreased to reflect their in-game utility relative to DX and IQ. Also, point costs for changing these four attributes have been made linear, which gets rid of the weird bump in 3rd ed. and looks prettier, though I will not go so far as to say a linear cost progression is necessarily the right way to go. Since probabilities of success follow a nice normal curve, we see decreasing returns on investment either way, but less severely with the linear costs.
I am also a big fan of many powers being turned into "advantages", and the wide variety of modifiers available to customize how the powers work and how much they cost. I haven't taken the system for a ride yet, but it looks good.
The main downside is how bulky it is. Well, maybe it's an upside. My impulse is to say that players should make characters by first thinking up a detailed character concept, then going through the books from the beginning writing down what that character would cost, then selecting deleting that go over the point limit for the campaign, or enhancing what's there if the limit has not been reached. There's way too much to memorize or keep in mind to make quick characters, but likewise it is far harder than other systems to game. It is less obvious how to make characters that are uniformly better than others for the same points. I'll keep poking at it over time.
Now that I've got falling deaths out of my system, I'm thinking of working on analyses and guides for strength scales or movement speeds. I've got some good numbers hanging around, but not as much time as I'd like.