I was looking to buy a Smart vest but still did not make a final decision. I tried it in a store and it was OK. It can fit under my touring jacket and probably under my leather jacket with a comfortable cut. No chance it would fit under a leather jacket with a more race/sport cut and probably it would be difficult to wear under a short summer mesh jacket, but other then that it looks good. Not too heavy, feels comfortable on body. I would say it is not designed to go over the jacket even though it is advertised to go both ways. Then again I question myself, should I rather buy a good body vest with front and rear protector so that I can use it with all my jackets and also in enduro riding setup...
Welcome to the family @Hans1967 !! Joined a month ago and now this is your first post? How about introducing yourself with a post in the "New Members" section?
What MV do you own? and where in Germany are you located?
I opted for Alpinestars Tech Air 5 vest.
Fitting only under a (suitable) jacket (in my case a comfortable cut leather jacket).
I have it since about 3 months and I am pretty happy with its weight and breathability. I trust its tech will work well the day I decide to kiss again the road. I would consider it in alternative to the Dainese vest.
Also when it comes to suits, I find the modularity of Alpinestars a plus point. The total integration can be annoying when you have to miss the suit for weeks waiting for inspection/recharge/repair.