Reached level 53 with my good old radiation build before getting distracted while watching TV and getting blown up by a bomb-ship cluster.
The UI feels more polished and the new enemy is nice, though I don't fully understand when it starts shooting. It is though as hell, thats for sure. The weapon testing is great, very welcome addition.
Later this week I will try to use the more advanced modifiers in my builds, for my run I didn't get any of them till round 20+ and at that point my build was fully online and replacing anything would have reduced its power.