It totally is Zen. 🙂 It's theory wank, but designers and tinkerers love theory wank!
GURPS is a hybrid of a "details matter" and "reason from effect" game. Equipment, the physics of actions and the world, the skills. Tons of details (differentiations). The "Powers" system of ads/disads, etc. starts with moderate details but allows you to customize with the "reason from effect" paradigm. You can take some power constructs and bend them to things you want to accomplish that don't necessarily fit the name of the power. GURPS seems more fiddly than it is because of the hybrid. Sometimes you are constructing a power that obviously the power you want. Other times you end up in a fog trying to file the rough edges of something where the details are not helping.
HERO is mostly all "reason from effect". It's about creating a generic framework of system bits that then cover the majority of "things you can do, things you are made of, things that can happen to you". It forgoes lots of the differentiation of similar things for flexibility. All these powers are basically building blocks you use to construct "all the things". There is a consistency then to those things. Sometimes however, these things can get "weird". So, a gun being set up as a "beam"... I'm like "that's not a beam! it's a projectile!" and HERO is like "dude, relax, it's just a mechanic. Describe it how you want to." 😄
The truth is they are both great games with savvy design and TONS of thought put into them. I own tons of GURPS 4e and GM'd it for a long time (and played/GM'd a ton of HERO 5er before that!). I've moved back towards HERO because it focuses on the details I want. I love magic, powers and the like. I want the ability to customize those the most. I don't care so much for equipment lists, skill lists, or even physics emulators. HERO leans more "story-based" in this regard. In my opinion it has less calculations or laser-specific rules that just fits how I GM.
It comes down to preferences. Each person is going to find the parts in one of these systems they prefer over the over; and then likely choose it because it fits them. The rest of the debate is just theory, highly subjective and difficult to measure.
Just my two cents...