Hi! To be honest, I occasionally take a peek at Scryer Prolog, but it seems to have a lot of grand ambitions without showing a lot of progress towards meeting them; it’s hard to see why I should care about it compared to a very mature and full-featured system like SWI prolog.
Since you say you are involved in this project, please take this opportunity to change my mind! :-)
Yeah, this is a really nice feature; on the couple of rare occasions where an update completely borked things I was able to go from unbootable to everything back up and running in half an hour.