It's hard to tell reliable sellers on Discogs, especially if you're looking for specific titles. Unfortunately, buying records through Discogs appears to be a gamble, as this thread demonstrates. I got lucky when I ordered my first (and so far only) LP through a Discogs seller; he offered me a discount, having accidentally over-graded it. This is not the case with all sellers. I would say that if you're looking for an album that is readily available, check seller feedback and choose the seller with the most positive feedback. I always check their negative feedback to see if any complaints are valid; very frequently, the seller will receive negative feedback based on something unreasonable (like the item not arriving within three days of shipment). If you think that the negative feedback is unwarranted and undeserved, check the positive feedback, and if you like what you see, place the order. Given the number of people who have trouble buying records through Discogs, I would say don't feel bad about paying a little bit more to guarantee you're getting what you want. It also never hurts to send the seller a message asking for details about the item, shipping, or anything else. I find that sellers are almost always friendly about this, it never hurts to talk to them.