It's basically a combination of 5/3/1 and Westside.
If it's good enough for Mark Bell, and a tonne of ex-Westside lifters, to hit PRs off then it's good enough for plebs like us
That and Lilly himself has added 70kg or something like that to his squat in the past year, and 40-odd kg on bench
I like it cos it combines ME, RE and DE using the main lifts themselves, as well as only having 1 heavy day a week (I've struggled to maintain 2 on the typical WSB split)
There's also enough variation to cater to my training ADD lol
That said it definitely seems as though it is better suited to unequipped than equipped lifters if the results of Lilly's training crew is anything to go by (they're all hella strong but get basically zero out of their equipment)