I just upgraded from MC13 to 15. So far I absolutely love it. The new features have been excellent and I'm shocked you guys came up with even more ways to customize views. I am having one slight issue so far with video cover art.
When I first imported my old library, some of my files had their cover art replaced. Specifically the first episode in a handful of random TV series, and always with the same image (the first season of Numb3rs.) I didn't think much about it and assumed something was messed up with the paths when I switched to 15. I replaced all the afflicted cover art and everything was fine for a couple of days, but now I seem to have a whole whack-a-mole situation going on with video art.
While the first problem actually applied to the cover art associated with the file, the newest one seems to only be affecting the preview pop-up.
As you can see from the tag window, the correct art is associated with the file, but the pop-up is showing another picture entirely. Then, if I re-add the cover art again:
It appears to have fixed the problem, but then if I go to another series
There it is again. It's always of the last image I added. Only the first video in a series. And it doesn't affect all of them, just a handful of random series.