Oddly good.

My commute is ~25 miles one way. In my Leaf, going 65+ mph, I usually burn 25-35 miles off the charge. If I'm in stop-and-go traffic half the way I usually burn 10-15 miles for the same trip.

I've taken quite a few trips where I arrived at my destination with the same amount of battery as when I left. I've yet to arrive with more charge but maybe one day...

For buses it is very effective, since they stop every few blocks, whether the stop signal is red or not. It also makes for a huge saving on brake repair and replacement, which you can imagine is a big expense for buses.

Also city buses usually drive under 200 miles a day and then sit overnight so you can have relatively small batteries. All in all, it is hard to think of a type of vehicle where battery power makes more economic sense, and gives you more advantages over ICE.

It depends a lot on how you're driving. Numbers as high as 70% have been published, but I believe that requires the deceleration profile to be ideal, and that might not be the most comfortable one for passengers.