Hello, thanks for reading and for the questions.
As I mentioned in the review, I was specifically covering the N1, as the B1 is more of a refresh of the older design with some of the new features packed in.
I haven’t heard anything about the long-term build quality of the B1, and my personal pair of 950BT’s didn’t break while I owned it or in the hands of the friend I eventually gave it to…but Sony’s audio products are sometimes hit or miss in that department for sure. We all remember the 1000X issue.
Sorry, I don’t personally know more about it! I hope the place you bought from has a good return policy just in case, and in theory, Sony has a decent warranty.
As for Bluetooth lag, in movies it should be okay, especially if you’re using the same source device as you used with your Bluedios. These days, most lag/sync issues for movies are handled on the playback device itself unless the headphones specifically stop it. The computer/phone will attempt to delay the playback a bit to keep everything in sync.
This is a lot harder to do in a higher intensity situation like a game, which is why Bluetooth audio and mobile gaming don’t always go together. Again, this is going to come down to a device-by-device basis…and I’ve only used the N1, not the B1.
So, what I’ve basically done here is written a lot of words that don’t totally answer any of your questions. Sorry I can’t be of more help!