I think it depends on what your using it for, newconstruction, I used to spray close to 100 gallons a day, I nedded a rig that could run two lines, and preffered gas. Speedflow 5500 I think it was,awesome machine
Now I only do repaint, the most we sparay is maybe 10 gallons in a day, my all time favorite for this would be a speedflow 3500, it has gas and electric motor can switch out in 5 minutes, I dont have this machine anymore
We currently run a greco, their small version, its just electric, and is fine for what we do.
It really depends on what your going to use it for, But speedflow is my favorite brand