Frankly, I find Installation events a lot more fun than most other anti-human combat activities in the game. Ships seem a bit harder than regular RES pirates, and there some objectives to play. If they only weren't bugged and broke as all hell and there was any reason to go into it, I'd do it a lot more often.
Pirate Activity is good, but only if you want to fight bullet sponges left and right. They are not particularly challenging in combat, pretty close to higher rank targets in CZs, but take forever to take out, unless you run something like a Vette, with insane firepower. Payouts also aren't great in comparison to other activities, since you down a lot more ships in RES/CNB/etc, so even if individual ship bounty is bigger, it falls off a cliff with sheer killcount.
Wish targets in all activities would be aligned to CMDR combat rank/engineering, making enemies beefed up, for game not feel like some anime where you murder 500 ships alone...