It's fairly powerful, and the Autorouter is a relatively good one. Go to
https://www.olimex.com and get
https://www.olimex.com/pcb/8mils.dru and
https://www.olimex.com/pcb/10mils.dru ; they're good design rule checkers for Eagle.
It's not without quirks- copying parts from one library to another is painful. But it's outnumbered by features that DO work well.
It doesn't crash. This is a big plus, try Protel (crapware with far more spent on sales/marketing than on engineering) and you'll see what I mean.