When not riding I seldom use a jacket - always a vest.
On the bike always vest under the jacket if cold or vest by itself if moderate.
I like light leather or polar tech for under a jacket. Heavier and lined and fleeced for vest only.
Nylon insulated also works well.
As for collars I like them on the polar tech helps stop the neck draft and when wearing a vest alone. draft. Not lay down wing collars but stand up/zip up collars.
This is the idea I was thinking about, wear the vest instead of a jacket, if the temps get cooler put a sweater on over or under the vest. But use the vest as the main rider wear instead of a jacket since most of the time its hot here. Seems to me it could be much more comfortable with the vest to ride in more situations.
The vest I bought was a fairly heavy leather riding type vest with the protection in the back panel made by Street and Steel.
Wondering how many use vests and yes it would be a great place for VRCC patches.