I basically agree with Michael Fisher in his two-part review (and most of his reviews for that matter), and with the Lumia 950XL, I still agree with him.
I have a Lumia 1020 which, at the time I bought it, was running Windows Phone 8. In comparison to Windows 10 Mobile, Windows Phone 8 (and Windows Phone 8.1) were complete and finished Operating Systems, while W10M is still under continuous development (started from a really incomplete OS which has been built on update after update in the Insider program). Now, W10M is technically no longer in BETA*. But when I held the Lumia 950XL, it just didn't have that "wow factor" for me to really want it. My L1020 looks and feels like a professional gadget; the L950XL didn't.
So to answer your questions:
- Yes, some of those bugs are still there. The reboots are less frequent now though based on user reports.
- Yes, I've experienced some (if not all) of them.
- Yes, he is right about that. There is the "Windows Insider" track where you can receive updates more frequently than the "average consumer" and so far the latest updates have made W10M more reliable and more stable.
*W10M used to be in BETA (shortly before he made that video), but now it is technically no longer "BETA" since it is already available to consumers through consumer products (i.e. L950, L950XL, L550). The OS version in these devices are not as updated as those available in the Insider tracks. However, we're expecting that the consumer versions will soon be matched up with the Insider versions once most (if not all) bugs have been addressed from Insider versions.
I'm still not getting a Lumia 950 XL even if W10M matures completely - but that's my personal preference and bias against the overall physical appeal of the device, and because I'm still looking (and hoping) for a worthy L1020 successor.