Long time no hear, Mikey.
I honestly can't say for myself how good they are compared to similar offerings from SQ, CX and so forth. Acquaintance of mine did say that it was a useful feature, but it didn't like he made heavy use of it at all.
Here's the link to the picture, if you haven't seen it already.
I'm aware that Asiana has PTVs on some of its fleet.