Some guys like it and some guys don't, but I found that I made way more money doing service work than working for a GC.
If you can do 4 or 5 service calls a day that's not to bad. Most homeowners will pay you right then so there is no billing and you have 4 or 5 new customers who will refer you to their friends. A GC will never refer you because he's always afraid that you'll be busy when he needs you.
I used to do most of my work T & M with a minimum of course, but most people really liked the fact that I worked fast and if I got that ceiling fan installed in an hour I got paid for an hour and if it took me three because I ran into problems it took me three, but I didn't go in and charge for three hours and leave after one. It's not always about how much you can make. If you treat your customers right, the money will come. I've had customers that I've worked for for over 20 years, I might only hear from them every 3 or 4 years, but they always call me back.
Charge a fair price, do top quality work, show up when you say you're going to.
Good luck.