There will never be a consensus on this because everyone has their own personal lifestyle preferences and ambitions.
I left easyjet 7 years ago and am now mid 30’s, long haul BA, with a young family at home. Personally I cannot think of anything more fatiguing than flying short haul day trips, especially multiple earlies, and then going home to young children every single day. That has got to be seriously hard work. I go down route and get a couple of good nights kip, see and do things I’d never otherwise get a chance to and when I get home, generally I have a good stretch of time off which is 100% focused on family stuff. If one day my priorities change when the kids are older, I’ll bid back to short haul. That variety and flexibility is one of the biggest advantages of working for BA in my opinion. Whatever fleet you join on, you are not committing yourself to one particular lifestyle forever. And this is where people frequently get obsessed with the wrong thing. A 5 year initial freeze shouldn’t put people off considering the next, in some cases, 30-35 years of their career.
Ultimately though how can anyone say with any confidence that they are happier or less happy than they would have been had they taken a different decision. I haven’t worked as a part time easyjet captain, or in the charter world, or on private jets so I can’t know for sure I wouldn’t be happier doing that. You just make the best call you can at the time based on the most information you can get your hands on. Second guessing it down the line isn’t likely to bring you much happiness.
The fact remains not many people ever leave BA whereas the queue to join is usually around the block. You can’t escape the conclusion that there must be something in that.
EDIT: crossed with the post above which covers some of the same points.