Just some quick impressions now that I've had the HD in my Suhr for a few weeks:
Polar opposite of the stock SSV. The SSV is good if you're going for that vintage 80s kind of fuzzy grind, but I didn't care for it all that much.
The HD is simply amazing. I'm playing it through a Guytron GT100 with an EarCandy BuzzBomb 2x12 (two Guytron Bigtone 55 speakers, best speakers I've played yet). This pickup is very, very articulate. It cleans up decently enough (better than the SSV did) and has a very organic, if hi-fi sounding tone. Chorus-riddled leads are unbeatable. My band covers Comfortably Numb for our set, and the first time I kicked in the first lead part, I almost cr@pped my pants :D If anyone isn't sure which pickup they should get for an alder-bodied Strat style guitar, I'd say the HD is it. It will do just about anything. As I understand it, it's not as tight as some of the other modern BKP line, but I don't play chugga-chugga-technical metal, so I could care less. It really brings out that woody alder tone, especially with the volume rolled off. It also splits well with the middle pickup for that #2 Strat quack.
Overall I'm very pleased. I didn't know what to make of it when I first put it in, but once I tweaked the height I was golden.
I also have a set of VHII's on the way for my all-mahogany maple-top G&L Legacy 2HB. I used to dig the Tom Andersons in it, but since I installed the HD in my Suhr, it's been hanging on my wall collecting dust...
-Russ