I bought this sprayer mainly to spray polyurethane finishes onto some homemade furniture. It works great for that purpose. I bought a gallon of Minwax Polycrylic about a year ago and I have not been all that successful at brushing it on and getting a mirror-smooth finish without bubbles. This sprayer works quite well for spraying polycrylic and give a much better finish than brushing. I spray the Polycrylic without thinning and it works great. While the finish is not mirror smooth, it is fairly good. I found that 3-4 coats of Polycrylic with light sanding inbetween makes for a nice finish.
Be careful, though. This will apply a LOT of finish quickly and can lead to drips if you aren’t careful.
I have also sprayed water based primer with this (Kilz2 & Bullseye) but they both need to be thinned to work. By thinning these primers, they do not cover as well and need multiple (2-3) coats to cover well. I found this is somewhat a pain, so I do not spray the primers as much any more.