[my67c20]

What is your budget? Now double it. What is your electrical connection? How much space you got? How loud of a compressor will your neighbors tolerate? You mention that you would like it to be portable, which probably means horizontal tank. What type of surface would this portability option be used on? You mention painting and live in the bay area, which means a descent air dryer, so you need to factor that in as well. Keep in mind if you buy used people are selling cause they have new, so why they selling it. Also if its 220, they may not have the thing connected so you can hear it run. Does not mean that something new does not have a noise and mechanical issue either, but it does come with tech support to vent to. Bottom line, do you homework and buy something that will do the job today and in the future. Oh and I did a quick craigslist search a there is a lot of used stuff out there, although not inexpensive.