I have a Medium (40). I wear Medium in the Maritime, Yosemite, Variegated Stripe Popover, and Cherry Blossom shirts; 40 in the Telegraph jackets. I would call the Jacket fitted. All the shirts/jackets I mentioned are a bit looser - maybe calling them tailored (slightly looser, but not loose/baggy). The wrists can be a little tight with a watch on - same as the Maritime is for me though - so don't expect to wear a diver or smart watch comfortably. The color is fantastic. The fit in general is quite close - I can't wear a sweater or anything heavy under it - but that's kind of the style. The chest is tight but it was Golden Bear's expectation that this would relax as the jacket broke in - I feel like it's most comfortable in the "riding a motorcycle" arm position where it makes your arms/shoulders want to be more forward. Like I said though, I asked TS and they asked GB and the response was "that is expected and should form to you with wear." The weather has been less than cooperative lately so I haven't worn mine as much as I'd like but I believe @mikegnthensome said TS was told "about a month of daily wear" will break it in nicely.
I know some people were questioning the quality and fit, but had no frame of reference on either since they weren't buying one to try. It's never gonna be the custom MTM jacket that leather-heads want it to be, but it's certainly the best leather jacket I've owned/handled in my limited experience (I've had a couple, but I also know a reasonable bit about leather from my shoe habit). I got it via pre-order obviously so I paid a decent chunk less than the current price, but that's not to say I wouldn't still consider it - I'd just have to justify it that much more to my wife .
Thanks for the detailed reply!
My Small shirt also has a slightly loose fit, so it sounds like a Small would be right for me. Not really looking to layer it. The color is awesome, and is primarily what attracted me to the jacket.
This or an Aero...I guess I have till tonight to decide if I want to knock a bit off the price. :)