I haven't encountered any crashes on 1.9.0 outside of certain arcade games. It feels pretty "stable" overall. Ozone works now as well.
However, it feels like it got a little slower to load ROMs within the past one or two versions. Even with the mitigations discussed several pages back (ie, remove the "info" and "assets" folders, don't use playlists or history, manually load cores and ROMs), it still seems to take a few seconds longer than it did around 1.8.5 or so. I think there were some recent changes to the way ROMs are loaded that might account for this.
Also, turning Achievements on slows most cores down to the point of being unplayable now. I don't know what changed, and maybe it's just my own setup, but at one point it was usable and now it's not.
I'm thinking of going back a few versions myself.