While I haven't tried this one. I would recommend a different base layer if you are looking for a warm form fitting layer made for people with long arms.

First of all, the Marmot is Polartec (Polartec Power Stretch (88% polyester, 12% elastane)). It seems a little pricey for a solution like this IMHO, regardless of the full zipper.

My recommendation would be the Arc'teryx Phase SV Zip-Neck Top. The Phasic SV material has better odor retention properties and it's warmer. Also I think your body type fits their styling better. Personally I would prefer not to have the full zipper as well, but that is a matter of taste.

I'm actually looking for a mid weight fleece, not a performance shirt that is my base layer. I want this product to be very warm, but also fairly form fitting, fit inside my hard/soft shell, be able to be worn by itself in cool weather, and be longer than average arm and body length. Thanks for the suggestion though, but that Arc'teryx shirt will be too thin and on my body, not an actual fleece jacket like I'm looking for. Any other suggestions? Thanks