It's two years later, and I find myself eyeing HARP every few months. I still enjoy reading around in the core rules and in the Folkways supplement, and I really like chargen in HARP - it has all the right building blocks and offers flexibility without being overwhelming. I still wouldn't know about the actual gameplay, because I never brought it to the table, but I played a lot of MERP back in the days, so I think I have a general idea.
I think it scratches an early nineties itch for me that keeps getting stronger. That was the time when I started gaming "seriously", discovering RPGs like CoC, Stormbringer, Pendragon, MERP and Shadowrun, and what mattered most to me back then was being able to create sufficiently individualized characters that felt true to the fiction that I liked to read and developed organically. During the 90s, these ideas were often burdened with more and more rules, but the first games of that type struck a good balance, as far as I am concerned, and HARP feels like that. A little clunky sometimes, a little mired in legacy stuff (like buying characteristics on a scale of 1-100+ just to then convert them into bonuses), but generally aiming for an admirable diversity and plausibility in characters.
Also, crit tables that make you think twice about starting combat. Or thrice.
EDIT: Also, at this point, I kind of like how it is supported by its publisher. They are glacial, but still, about once a year, a new book comes out, and they stick to it and keep supporting HARP. I hope they will keep on doing it (Rolemaster Unified seems a lot more succesful, so I fear that they might end up diverting all of their energies to it ...).