I'm not familiar with that model gun. Devilbiss is a good company that makes good stuff and you can get replacement parts with no problem. I like to go with name brand tools if I want them to work right for a long time. Gravity feed guns flow paint more easily than siphon type paint guns. They have a shorter internal paint path which means there is less to clean up. I have tried several and have not found a siphon hvlp gun that worked well for me. If you are going to go with hvlp, go with a gravity paint gun.
A paint gun that includes extra air caps and/or fluid tips has extra value. These are not cheap to buy separately. Primer surfacer can be sprayed with the larger number orifice and your color and clear with the smaller. Contrary to what you may think, paint atomizes better with the smaller number orifice. Some think that you use the big tip to flow a lot on, but the reality is to use the small tip to break up the spray into the tinyest droplets to get the finish to be smoother. I use a 1.3 tip for shooting high solids clear and 1.3 and 1.4 tips for shooting base colors.
Jim "Oldgas" Potts Big time body shop tech