For me, the stand-up specials like Dave Chapelle and Louis CK alone are huge and welcome additions, never mind the many, very good lesser known comedy specials on there.
Their agreement with Dreamworks has only helped, allowing me to enjoy surprisingly good films like Zootopia.
Even great cable channels like FX (The Americans, Legion) and AMC (Mad Men, Better Call Saul) are not available for any reasonable price as standalone cable packages, so I'm not sure what the comparison is in terms of quality. HBO at 15/month?
But even HBO shows are hit-or-miss. And while their movie selection is generally pretty great, I still find myself not watching it all that much.
It seems to me that Netflix provides a pretty high level of content at their price point.