First you can't deny that Steve Jackson games are consummate production artists, and their work is a pleasure to look at and read. But does the work stand up to the high level of publication quality? For me it does on several counts. I like the skill system, even though the performance curve could be considered less than optimal for gameplay. Which gets to the heart of he reason to really love GURPS--it is very realistic. If you want to run a hard core gritty and realistic fantasy campaign do it with GURPS. Modern realistic campaigns also work well with GURPS. But as had been said many times Supers and High Fantasy, not so much.
But this isn't the real reason that causes me to hesitate in regards to GURPS. I find GURPS a little "too" generic for me. I feel stupid even writing that, as obviously this just means that I'm agreeing GURPS has done what it set out to do. However, when held up next to Hero, GURPS comes in second place as a truly elegant generic system. GURPS has built on modularity depending on the genre or type of game you desire to play. This has generated new rule sets in addition to the core model. I can't really say their is a core PC build mechanic beyond point buy with GURPS as different systems are added based on need.
Hero on the other hand is built around a core idea. In many ways it is "more" generic than GURPS. Hero takes a few vague concepts out of which you build your PC and the genre world in which you wish to play. GURPS has more modules specifically built for certain types of play. You don't quite have to build everything from the ground up. GURPS already defines many of the speculative physics by which every game world works. For instance GURPS has a fireball spell--Hero ahs no such thing unless you build it. Some might find this helpful, others might find it limiting. Either way you are dealing with generic systems; just different based on how much you wish to put together for yourself or have put together for you.
The problem for me with each system is the "genericness" of each of them. Although both have great world books associated with them, GURPS TransHuman Space and Hero Champions for one example of each. Nonetheless, I still feel as if the core system is a bit bland. And if you play Champions or TH Space you default to those books instead of the basic books themselves. That each world or genre almost requires it's own iteration of books by which the "chosen" (read house) rules are selected and defined within that world.
Not sure I'm being too clear here, but I'm not really sure my feelings are accurate either. But it is what it is.
And then we have