I'd also encourage you to buy from a store where you can try them on. PB has em cheap on sale at times and there look and fucntion well.

My PB jerseys bought in store fit well and are XL
Hincapie bought online are L and fit well
Louis Garneau bought online are L and are WAY too big. Medium would have been better.

In other words depending on what brand I buy, I'm either a medium, L or XL.