I've ordered from DoOrDice about 3 times. I've had good experiences with them. Their prices are usually good and shipping costs seem about average. The only downside is that the UPS ground shipping usually takes a full week to travel from California to Minnesota.
FYI, if you want to do comparison shopping, two other stores I've dealt with and have good experiences with are
www.nobleknight.com and
www.gameoutfitter.com. I've met the owner of Noble Knight and he does a fantastic job of packaging his merchandice. He has a huge variety of stuff including tons of OOP material. Since it ships from Wisconsin, even the cheapest shipping option tends to arrive in about 2 days. Game Outfitter is based in Duluth, Minnesota, so I wind up paying sales tax on that, but the wierd thing is their shipping originates from somewhere out east, so it takes about a week for that to arrive here as well.
If you're concerned solely with price, GameOutfitter typically has the lowest price of these three followed closely by DoOrDice and then Noble Knight.
If you're concerned with selection, Noble Knight has the largest by far. DoOrDice is next, followed by GameOutfitter.
If you're concerned with cheap, but timely shipping, then I'd recommend GameOutfitter for US east coast, DoOrDice for US west coast, and Noble Knight for central US.