I am embarrassed to admit that I forgot to take pictures of the comparison of the Harbor Freight 68843 vs the Devilbiss Finishline 4 (FLG-670).
Just to make sure this is clear, this is not the cheaper HF purple gun, it is the $60 chrome HF gun.
I cannot take the pictures now because after the first 2 coats, we finished the whole hood with the Finishline gun.
We still has some orange peel to deal with, but it is the first time either of sprayed this type of paint.
I previously used the HF 68843 to spray some eastwood/kirker hot rod satin black urethane on a riding lawn mower (practice project #1), which is considered a "high solids" paint, and was thicker than single stage Kirker Urethane jet/gloss black we recently painted.
Previous experience with HF 68843:
With the satin black, the HF 68843 seemed to do OK, finish was a tad more textured that I would have liked, but I also didn't block the surface as well as I could have either. I had a couple of dirt spots (I assume it was dirt spots vs solvent pop or moisture issues) but I don't think it was the fault of the gun... And those spots were only present in curved/convex type areas where the air was swirling a little because of the the radius I was spraying around close to bends and/or 90degree angles. I can post some pics and edit when I can get the pics off the phone.
With the high solids satin, I had to add some reducer to that paint because it was striping really bad, and I had trouble keeping a wet edge. Even thinned, it still stripped, but when dry the striped appearance went away.
On to painting a car hood with the HF 68843 vs Finishline4:
This paint was the kirker single stage gloss black urethane.
All done at the same time (90 degrees and HUMID) swapping between the 68843 and the FLG4, same air supply; one side painted with HF gun, other side with the FLG4.
The finishline 4 laid the paint down in a much wider fan, and seemed to atomize more evenly and keep a wet edge much easier. I could not seem to adjust the HF gun to maintain a good wet edge. The middle of the HF pattern seemed much wetter than edges of the much smaller fan; even when overlapping by half or more, the edge seemed to kinda dry the middle wet portion of the previous pass.
We purposely laid the first coat thinner and a little drier, but the second coat was a wet coat. After the second second coat, the finish on the HF side was stripped... I attempted to correct this with more fluid and that didn't seem to help much.
So we ended up doing the whole third coat with the FLG4.
We ended up with a lot more dirt nibs in the paint than we had hopped for, but we were rushing the previous blocking session and didn't clean the floor well. The test was going to happen because this was the day my buddy came with the FLG4. We also had more orange peel than we had hopped for with both guns, but I believe further adjustment and/or reduction will clean that up to some degree.
I can tell you this, I am a cheap SOB, and I was thinking the difference would need to be quite vast if I was going to talk myself into buying the FLG4. But the difference was indeed enough that I went ahead and ordered myself an FLG4 last night.
I imagine that if I knew more about what I was doing and knew how to adjust the gun more properly and all the HF gun might have done much better. It really did OK on the satin black paint on the mower... I know people have laid down plenty of decent paintjobs with even the $10 HF purple guns, but with no experience and very little time twisting the knobs and such, the FLG4 was much easier to use, and had had a fan probably 3 times wider than the $60 HF 68843 gun.
Hope this information is useful to others...