To each his own I suppose. Once you realize that money over about $100k/year won't buy you anything that will actually make you happy for more than a short time, the world looks a lot different. Once you eliminate the money part, I guess the differences between mainline and regional flying come down to personal preference. Do you prefer fewer, longer legs to big cities or more, shorter legs to smaller cities where you're allowed to have dinner with your crew? No right answer. It just depends on the person.