Wanted your guy's take/opinions/experience.  The lady at AWS that I spoke with on the phone earlier today said I should likely go with a medium, but I figure I'd ask you guy's to see to get some confirmation so I avoid hassle and order right the first time.

I'm 6', 215lbs, chest measures ~44", wear a large T-shirt and have a ~33" waist. I could stand to trim down 15-20lbs and likely will in the near future, but I'm in otherwise great physical shape with a fair bit of muscle.

You guys that have been there and done that... what size should I go with?

No experience with AWS, but I have a 46" chest and wear a medium BFG PLATEMinus carrier with the appropriate plates.

I believe they're sized based on sapi plate size. Medium for a medium sapi, etc. With me being 5'9ish 175, the medium is about the perfect size for where the plates need to sit. My advice is decide what size plates work for you and size off that.

You are correct.

As a decent measure, your plate needs to span your nipples (rather the vital zone that lies beneath).

Well, I measure just a touch over 10" in that regards.

Balance coverage against mobility.  Sounds like you should be wearing a large SAPI or ESAPI.