Mad thread! We love vests here.Its a nightmare trying to get a vest top for 6yo DS. He hates clothes in general, so a vest is an achievement for us.
I generally buy the John Lewis ones designed as undergarments in dark colours - navy, black, grey etc. No logos/pictures. Although I did have some nice Captain Tortue ones a few years ago.
DS looks absolutely ravishing in them. I mean it. They really suit him as he is slim with broad shoulders. He has olive skin so I don't worry overly about burning.