Primer guns tend to get layed around and banged up during use, a $20 horror freight will get primer on a vehicle and if primer kicks off in it it's not a big deal. Kinda what I call a disposable gun. I do not like how they spray base or clear. I have a 3m accuspray. We pretty much use them as primer guns around the shop with 1.6/1.8/ tips. I have also seen them broken in 2 pieces. Astro guns are made by Star. I have a couple. One is the newer style in a 2.0 for polyester primers. It works well for that and Star has a pretty good reputation. I believe they also offer one of those Euro models in a trans-tech/RP version as well. The other is a 25 y/o Sata 90b knockoff. Also have the kit 340s mentions. The mini gun didn't last long before it started dripping fluid out the nozzle. Both guns spray like and pretty closely resemble Devilbiss starting line guns. The larger one is still kind of a downsized gun with a smaller fan and less paint volume but sprays pretty nice for hvlp.
Hvlp are air hogs. Hte, TE, trans tech, rp type guns give up about 5% transfer efficiency to an hvlp but at less air consumption and typically a flatter finish. I don't typically like how lower end hvlp lay down clears and single stage. My go to guns are Iwata Air gunsa az3 HTE for sealers and occasional small parts, Devilbiss base specific hvlp Tekna for base, and a Devilbiss + or a different Techna that is set up with TE aircap for clears. Typically, 1.3 for MS clears and 1.4 for HS clears.