I purchased 15 stamp bags of heroin from Theworldofthed for $100+$7 shipping, here's my review:
Communication : He did respond to my message, but I asked about weight, consistency, his willingness to cut deals on bulk, etc; he simply responded that his product was consistent. Fair enough, he's not interested in off market deals or bulk.
Packaging : Arrived in standard packaging, though he used FoodSaver bag instead of MBB, for heroin I would have rather the extra bit of security. Good enough for domestic USA, I suppose, but I would rather my dope arrive extra stealthy.
Product : I've never bought a "stamp" bag before, but it's the same as a pack. It didn't last long enough for me to bother putting it on a scale, but my eyeball weight for it would be 3 stamps per .1 gram. So my total 15 stamps was approximately half a gram. As far as quality, well it wasn't bad, but it definitely wasn't up to par with the local stuff I buy $100/gram. I don't have much experience with regional qualities, so the best comparison I have for you is about 80-100mg of oxycodone.
Overall : He's legit, but as he's the first DNM dope I've bought I can't compare. If you have another hookup, I'd recommend going through that, but he delivered what he advertised. I've seen Theworldofthed on a few other markets, too, with the same picture.
His stamps are the lightest I've ever seen. Do yourself a favor and just avoid stamps entirely. If you're low on money go with pdxblack on agora or TE he has 45 dollar 1/4 gram listings and it's fire (unfortunatley tar but it's so good). He also hooks it up. Bestman365 on pandora is even better and has sample sizes right now. I ordered a half g and it was enormous.