So first real ride of season and I used my new Tekvest. About 200km ride.
First 5 minutes I noticed it. After that it was a non issue for me.
Heat wise it was a mild day and I wore a t shirt and a very thin long sleeve shirt. When we started out it was -8 or -10. A couple hours it had warmed up considerably to -2 ish and despite buying the least insulated Tekvest I was very warm
That being said it was a warm day and in tight and twisties I would have been warm anyhow.
Main thing for me was I did not feel it hinder my riding ability. Or lack there of.
Only thing was finding room for it at lunch table in restaurant!