I bought the SATA primer gun thinking it was a finish gun. $319. It lays sealer so smooth there's no nibs to knock down. Straight into your base coat. Then I bought the SATA Jet 3000 finish gun. The only paint gun that I had to really take some time to dial in. My Devilbiss that I could afford at that time were ready to spray, after cleaning the inside of course. The SATA Jet has many extra orifices to double atomize than my other guns. It was worth the $600 price. The Devilbiss guns did good at $135. Plastic cups are not a problem, no difference. All my new guns come with a plastic top. With the plastic tops on to shake up the laquer thinner to clean the gun causes them to pop off. Watch your eyes. The plastic also allowed me to enlarge the vent hole in the cap. Not much needed here but it helps when you get paint in the vent.