Trying to do an infestation on each tier 5 POI and jotting down a couple notes, still several I either haven't done yet or did as a tier 5 but not as a tier 6 infestation.
Red Mesa = Surprisingly easy for a tier 5 military POI because it's non-stop chokepoints, making it easy to manage packs. You can also aggro two of the last big packs from the top of the tent at the very beginning of the POI by shooting them through grating, making it a bit easier. If you're playing with loot reset the loot room is right near the beginning of the map. Probably my favorite and most run Tier 5.
Grover High School = Nasty as fuck. Aggro probably half the POI at once at the very beginning with no chokepoints, including vultures. Fortunately the AI is retarded and interferes with each other jumping off the roof which allowed me to space them out a bit, if they'd come down en masse i might have had to abandon. Loot is *right* in front of the front door of the school.
Higashi Pharmaceutical = Fairly easy packs until the end which will buttrape you if you dont flee back to a choke as soon as you aggro.
Crack a Book HQ = so easy it doesn't even feel like a Tier 5, relatively short and easy to deal with packs. Great POI to prioritize if you want to finish maxing crafting skills.
Shamway Factory = Fucking awful, long tedious map, constantly having packs all around you/falling through trap floors. Run once for the Sham recipe if you're a completionist, otherwise avoid like a zombie bite.
Navezgane Correctional = There are two tier 5 prison POIs, this one is in the northeast in the Snow Biome (in Navezgane) and kinda sucks. Poor chokes and mobs spawning behind you occasionally.
Haven Hotel = Terrible. Constant no-return dropoffs and mobs being dropped all around you. I did get several legendary components but savage country is available much earlier and is not nearly as much of a headache.
Last Sunset Nursing Home = I...barely remember this even though I just did it today. Middle of the road I guess.
Shotgun Messiah factory, Navezgane General, Athletics Complex, and Minotaur Theater I did as Tier 5s but not as infestations. From what I remember of doing it as a T5 I expect Shotgun Messiah will be just as awful as Shamway. Navezgane General is probably gonna be a snooze considering the lack of a biome difficulty modifier.
About to do Dishong for the first time ever.
*edit*
Dishong was fairly easy but also a huge waste of time. Took ages to get to the top and its too damn far away to ferry stuff back to the 4x4 so tons of loot went to waste.