The Italian pension system is generous but you have to be in it for many years to take advantage - that is IF there's any money left in the national pot by the time you get there
Minibase agreement at present so it's random roster pattern with 132 days off (? - somebody will correct me if I'm wrong).
Berlin is subject to the German contract
AFAIK which is also decent. Not sure about roster pattern but the German contract is also OK.
Barcelona is pretty rubbish financially compared to other more established bases as it's in the new 'style' of minibases with reduced T&Cs and flexi roster. It's in the same ballpark as LIS, OPO, NAP that sort of deal.
But as with all things, since you're going to actually be living and working there, just go with whatever base will give you the best lifestyle balance. Money isn't everything. Life is too short.