I've mostly used Northern brewer, I think they're great! I just used brewmasterswarehouse for an order I received today. I placed the order on Friday morning, by the afternoon they emailed me back saying one of the items was out of stock and would take a few days, so I said ok, no problem. They shipped it out by Tuesday, which was a lot sooner then expected for the item that was out of stock! Great customer service. They even offered to ship the item they did have in stock first and send the other one later if I wanted that option, but a hydrometer isn't really too useful without the test tube lol. I highly recommend those 2 places since I have experience with them, especially northern brewer