It really depends on the operation. With 121 it is more predictable what kind of job you will be getting. You know bases, schedule, pay etc when you apply. Part 91 is a different story. I know of 91 departments that are worse than bottom feeder regionals and some can offer better quality of life than the legacy airlines.

Personality goes a long way toward job satisfaction at a corporate dept. Are you going to be able to roll with schedule changes? Increased planning and dispatch responsibility? I have flown with 2 retired legacy pilots who loved 91 and 2 who couldn't handle it and were a complete pain to fly with because of the drama they brought with it.

A close friend just interviewed at UAL. His dad has worked there for 30+ years and recommends he stay at his corporate job because the company isn't what it used to be. Just his opinion after all the changes in the company and culture over the years. Would I quit my great 91 job and go to UAL? Probably. I guess the grass is always greener.