LHR or MPM?

Hey everyone! newbie here, well of course i know it will be piece of cake for many experienced players here who have these hubs but its just i really can't decide, my airline focuses on long to ultra long haul flights specifically, like just pure 168 hrs long haul flight that typically ranges from 21 to 35 hrs and i use aircraft like the il 96-300, 787-8's and some a380's maybe for the future once i grow up from this game, well back to the topic im just a newbie that currently have 5 silver stars and i don't want to make a regret with buying hubs specially because they feel expensive for me to buy and i saw that choosing the 2 hubs has its pros and cons lhr has a good balance of economy and business class and can fly almost everywhere using the il 96's and 787's and mpm has great economy and can also fly everywhere using the said aircrafts, i dunno i just want your opinions, now i don't really focus only on economy classes i also like to mix them with some few Business or First, so yeah what do you guys think?