I have purchased several pots from them, all at very low prices. They are serviceable, but even to my unschooled eye the material is clearly not as good as any of the somewhat more expensive vendors. The pour on some of them is slower than, say, the pour on Scott's pots at Yunnan Sourcing. My regular shu pot, however, is from them and it does produce a good pot of tea.
If this is a first or trial pot, I would definitely say go for it. The are real pots that do brew tea. The clay is not the best so they don't feel quite as nice, but the quality and workmanship are acceptable. If you collect more pots, you will likely want to move up. I have not tried any of their pricier pots; some of those may be quite good, but I don't know.
Yesterday I received the worst pot I have seen. It came from Yunnan Colorful on ebay. There are peculiar shiny areas and rough blobs of clay that should have been removed before firing. It looks like it may have been painted or glazed in order to look more like a traditional pot. I may never use this one, but it does give me a handy benchmark for what a truly low quality, dubious pot looks like!
The Teapot Gallery products are serious, low-end products unlike the Yunnan Colorful pot I got, which is just scary! Also, a lot of TeaChatters have purchased their first pots from Teapot Gallery.