I have 2 of these jackets and really like them for temps between 25 - 55 F. Possibly even lower then 25F, but haven't tried ridding in that range yet. I just vary the layers underneath to match the temps. I picked up both jackets for $37 on sale through Nashbar last year during holiday and closeout sales.

Sizing - I'm 180lbs with 42" chest and wear large. The jacket is a little loose, could wear medium, except the room accommodates multiple layers, so that's good.

I also have thermal jackets by Sugoi and Giordana and the Nashbar jacket isn't really that far behind (if at all) when comparing materials and construction. To me, spending more doesn't always improve function, the biggest different is graphics and eye appeal.

As for the zipper, not an issue and it's still a men's jacket in Euro style with the zipper pull on left.

If I were you, buy a second jacket in one size larger of a different color when these go on sale (< $40) again right after Thanksgiving. This way you'll be well equipped with tight or loose jackets if needing more or less layers underneath to match temps.