Quite a few threads on this topic in the archives. You might check there for more opinions. I use the Breathe-Cool system with the full face-mask. It provides nice cool air. Just be sure the pump is in the fresh air and away from the painting. Some have the same system but use the hood which is handy for sandblasting as well. If you wear glasses the face-mask becomes a little uncomfortable.
Downside is the air hose. The hose uses a plastic coil with the hose molded around it. The coil provides support for the hose to keep the line open. If the coil breaks the hose easily crimps and cuts off air flow. The coil breaks easily if you inadvertantly step on it and causes a leak. The coil also seems to become brittle over time. I just removed about 15 feet of hose and used and male water hose adapter to replace the end. Worked good. Make sure you get enough hose. I bought 75 feet and still have plenty left. Hope this helps.