Polygon is really positive on this and other house rules Brendan made. But it feels like the writer is either a fanboy or has no experience outside 5e. For example, some of the stuff they are praising as new and exciting in the linked house rules article existed in 13th Age before 5e was published -- it's not groundbreaking and new.
Same for the main article. They talk about leveling up when the players want, but that's doesn't seem to be true, since they talk about rolling their HPs and listing what options they want. So they've picked their class, rolled their HP, presumably gotten things like the proficiency, users per day, spell slots, it's just that they haven't finished choosing what options they want at that level.
If they really haven't levelled up, they'd be able to do things like multiclass mid combat when they choose to level up.
That's still exciting, but it's not what is listed on the tin at all. I like BLM doing that, but I dislike how Polygon is covering this -- either their writer lacks the basics of what they are covering or they lack integrity to try to get a better tagline.