you mention of good quality of life but I'd like to hear from LH people who've been in a few years.
I've been in 10 years, joining as a DEP on 777.
As probably mentioned, lifestyle means different things to different people. My preference is flying East with the odd Caribbean and South American trip for variety. I rarely go to the US, maybe twice a year. I can achieve this easily and I am about 35% from the bottom of the list.
Swapping and sector swapping is very popular and with luck you can re-write your whole roster.
Blind lines only by bidding mistakes, I was wiped recently as I underbid and was given 3x5 day trips for the month.
Can always get leave in summer, but have not really tried for Christmas.
Have the seniority to achieve Airbus SH captaincy but would think about maybe 787 instead, just for a change, but equally happy on the 777.
When I last looked we had 50 different destinations and there is usually enough time to make the most of any place.
My choice to go East, others like going West or beach or golf or kite surf of time at home or weekends at home. Consequently used to the time change, can sleep down route and have no issues forgetting about work and relaxing in the UK.