I was a remodelling contractor for about 20 years and I've hung and finished a fair amount of drywall myself. My skills are probably SOMEWHAT above the average DIYer but not anywhere near what the average pro has. I found that it was usually cheaper to the client to sub out even small jobs like a single bathroom, etc. Now that I'm retired (emphasis on the TIRED!) I do my own work, usually renting a lift if there's much high work. I'm not above bribing a neighbor's teenager to help out. The finishing is tedious, tiring (I won't use stilts) and slow. Pros have bazookas, mud boxes and many other specialty tools to speed up the work. Bottom line for me is to do my own work if I have time to spare but drywall work is one of the most cost effective trades to sub out.
The problem with education in the School of Hard Knocks is that by the time you're educated, you're too old to do anything.