I liked them a lot until I tried some on over the weekend. The Large was just a bit too loose, and the Med was definitely too tight on my temples. I was bummed. The Large was quite comfortable, but after breaking in, would have been too big.
There's no substitute for trying on before you buy.
Although I will add, the 400, 700, and 1000 all fit my head identically. Lots of other brands will have diff shapes for diff models.