The first ones I bought were Source Naturals. They were handy because I found
that 100mg was a bit much at first, so these were tablets and you could break them. But the 100mg size is big and a bit uncomfortable to swallow. After about two weeks, I increased to 100mg first thing in the morning.(no longer needing the 50mg size)

So I bought Country Life this time around. This is a small white capsule and the packaging is brown glass and more pharmaceutically presented.

It is not really expensive... at one a day it works out to about $7.50 a month.
It is much less expensive than the alpha lipoic I tried years ago. That didn't do anything for me. Like Brian, I like the energy it gives...must be sensitizing insulin. I have read some links where they are using it in studies for PCOS as well (which I had when I was younger).