>>96863169
Personally I like:

1) The reliance on dice to represent everything. Levels aren't just "You get +x to skill and stats XYZ", challenges aren't just "add up your static numbers and roll higher than baseline number 123". When you level up and become more skilled at something you get more or better dice to roll to beat challenges, which are represented by opposing dice whose rolls subtract from yours. It's more engaging for everyone and frees up a lot of pointless DM rolling.

2) There's no number bloat. In general, HP is kept very very low (usually 6-20) and armor doesn't cause misses but rather reduces damage, so fights feel gritty and dangerous and are fast. Even chump enemies remain threats throughout the party's life and I find players start to actually think about combat in 3 dimensions, instead of just charging in like they do in super hero simulators like D&D.

3) As a combination of the above 2, it's extremely easy to make up bullshit on the fly as a DM and it'll almost always work out. You don't have to factor in 3+ different static skill numbers, you don't need to math out the barbarian doing 1d12+4+3 x 2 damage but with 18 armor and 34 hit points while the rogue does 1d8+3+3d6 with 16 armor and 22 hit points etc etc etc. The low numbers and reliance on dice means you can rapidly conjure up threats and challenges.

It really is a good system, though I can see why conservative player groups used to D20+static numbers system wouldn't like it.