So far If The Bonnet Fits has been my favorite. She always responds promptly (huge bonus because I hate waiting for responses), her turn around time is fairly quick, and while I thought her bonnets were expensive to start I have found that they are well worth the price. Somehow I have ended up with four of her bonnets, including the magic hat and the little black bonnet.
I have a problem, but it is a fun one
My second favorite has been FUN Bonnets. She is based in Canada, but the two major drawbacks to her bonnets are the wait time (it was 12 weeks when I ordered my bonnet) and the bonnet was heavier than I expected. The heavier wouldn't be a big deal, except I am in the South where it is hot and humid all year round, so that limits this bonnets use to about 3-4 months out of the year. One plus, is even with the extra shipping costs to the US she is cheaper. I haven't used this bonnet a ton but I do think it will hold up just fine and it looks fabulous.
The fun FUN Bonnet
The third company is EDA Designs which makes her bonnets out of fabric. I love this bonnet in the summer because I can just toss it in the washer and don't have to worry about hand washing. Again, she is Canadian so shipping is a little more expensive if you are in the US, but her turn around time is very fast. In fact it took me longer to decide what I wanted than it did for her to make it. Granted I am sure I was testing her patience with my inability to make a decision (sorry), but she was always very prompt and polite in her responses. I don't love how the fabric sits on his head, I don't know if that is because of sizing or if they all sit like this (the picture is especially bad).
Of course it wouldn't be nearly as fun if I didn't have matching Dark Jewel Design brow bands to match all the bonnets. Sadly only one made the pictures. Whoops, I guess I will have to show that addiction at a later point. Stress shopping for the win!