I got mine yesterday, 7/13. 6-pack! I got an email in the morning saying they would be delivered Thursday (2 days later), yet a couple hours later they were in my hands. Cool.
The sound quality is completely average, but for me that is actually a step UP. The Sennheiser name makes me think that maybe slightly more thought than average was put into their design? Hopefully they'll be durable, as my headphones inevitably seem to lose audio on one side.
Although I still don't have any reason to believe they are not bootlegs, other than my faith in woot, and the fact that on the bootleg alert website (linked earlier in the comments), this model was not listed. (Although many other Sennheiser models were.) Oh, and the fact that they seem to work perfectly well.
They are slightly uncomfortable in my ears after about 30 minutes, but no more than the average earbuds. If I pull them out slightly so they aren't in as tight, that helps a bit. I didn't even bother with the little foam covers.
All in all, at six pairs for about $4 each, this is just what I've been looking for for more than a year now. If they last more than a couple months each, that's an even better deal, with my luck. Great deal, woot!