I've ordered from Redbubble before and, although the prices are a bit steep, it's amazing the quality of the shirts I've received. The cotton weight is a bit thin, but the shirts themselves are ridiculously soft and wonderful and I personally like the weight of the shirts. They also have online chat systems used for asking questions; the employees are very knowledgeable, friendly, and helpful.
The best part about Redbubble is the fact that artists can make their own designs and sell them which means that everything you get will be unique.
I don't think the people on here that keep complaining about shipping times realize that they actually have to custom make the shirts per order before shipping them out, so the actual production time is included in the time it takes to ship the T-shirts.
I also see someone claiming that the people giving this site "4-5 stars" are Redbubble employees while simultaneously claiming that Redbubble isn't a real company because they got an email from a "nonhuman". I'm not really sure how those two statements coincide with each-other, but in any case, I'm definitely not in affiliation with Redbubble. I just really like the shirts I received and will be receiving another awesome T-shirt soon.