I've used a devilbiss for over 30 years, and still use it everyday. If you are just using it for your own work it's fine. If you go into business you will want several kinds of guns.

The big knob on the bottom contorls how much paint flows through the gun. A good starting point is to screw it in all the way, then back it out one full turn. The small knob on top will adjust the fan size. Screw it all the way in, then back it out till the fan opens to it's widest point, then look at the spray to see if it looks even from tip to tip.

I always clean with lacquer thinner, and when spraying with sensitive paints, you would disassemble the gun, and clean the passages with a "bottle" style brush. Check with you paint store. If it gets really nasty, soak all of the parts in "gun cleaner". It take ANYTHING off!

It is not the gun or equipment that will make you a good painter. It is your own definition of what is "good enough".

You can produce nice paintwork with poor equipment and good workmanship,........but you cannot produce nice paintwork with good equipment and a poor workmanship.