wow I've finally received my HF-2 and I have to say that I'm really impressed. The bass is very present and the mids are quite powerful, which makes metal sound really heavy. Treble on the other hand is tamed down in comparison to other Grados which makes them really pleasant listening to.
I can also hear slightly less treble detail compared to the GS-1000 but I guess that's mainly because of more present mids on the HF-2s or sucked out mids on the GS-1000.
For rock I still seem to prefer the GS-1000. Here the HF-2s sound a bit closed in and too forward. The guitar and bass guitar is pushed just too much, while the GS-1000 give a larger sound stage and better instrument separation. It's really weird that the HF-2s are so great for metal but less so for rock.
But electronic music is where the HF-2s really shine. The bass makes kicks and basslines sound powerful and present (which is something I was lacking from Grados). The mids make synths thick and spacious and the treble isn't too forward as to distract with too loud ghost snares (in dnb), while still being detailed, present and crisp.
Jazz and classical music is more the territory of the GS-1000 so I don't expect much here but I'll have to check that later. I guess that they'll do fine enough for jazz.