I just toked up the next to last pinch of an Alaskan Thunderfuck bud I got from a friend. This is some good pot. I would surely call it sativa. I'm not an everyday smoker,but 1 toke gets me quite a bit higher than the Kali Mist I own. It's not as clear headed as KM, but it's more trippy than KM. It's a once in awhile smoke for me because I like KM's high better, but it's a nice kick in the ass now and then. If you are a potency lover, I'd bet you'd be impressed.
DR greenthumb is said to have put his homework into tracking back the line of ownership of the cut he's using to S1 for seeds. If the good Dr's version is as good as the bud I just smoked, I don't think you would feel ripped off by his price.
My friend didn't own the plant this bud came from, but I had him try to get a clone for me. It didn't work out. I was bummed.