I have a late 2014 Tekna. Shows the limit when it knows it. I wouldn't rely on it though, the data is years out of date and never updated.
True about cleaning the lenses, but I find it works really well in the dark. It has some kind of night vision, maybe just really good gain control and a bit more IR sensitivity than usual.Definitely - love the all-round monitor, however in this weather you do have to make sure to keep all 4 lenses clean, and it's not so great in the dark. Would love to have it on Tesla.
Speed limiter is handy too, especially in 20 or 30 zones.