Back in the days I have read but never played Hero (3rd edition). I came upon it some time after discovering GURPS for me, so I already had a generic system and had also convinced my players to play it. I didn't see a big advantage in switching to Hero and found the abstract nature of the rules too - well - abstract.
Also superheroes, which had a very strong presence in those rules, never interested me.
I would have loved to see Hero in action as a player, but never had the opportunity. Maybe ten years ago I stood in front of some Hero edition (black book with green daVinci human figure?) in a game shop and considered buying it. Well, size, price, and the inflexibility of my players let me put it back on the shelf.
Anyway, I'm still interested in the topic and will keep an eye open for Hero discussion here at ENWorld!