Nice, I just did too. Unfortunately this Starbucks is in the middle of a Safeway, and the Safeway people hate the Pokémon players who show up and raid there.
I actually have had two Mewtwo raids and just got my third invite. My 100 IV one is now at like 3800+ CP. My newest edition is at 78 IV but has perfect attack, so might still yet be a decent generalist if Mewtwo ends up being at all rare.
I don't think there is much point for most people in having more than 6-maxed out anything. I am even thinking of grinding down my number of legendary pokes to the best 6 or 7 each (currently at 13 to 14 of each legendary in case trading ever becomes a thing).
Is it even worth it to max out your mon? Maaaaybe the legendaries? I just don't see the value in spending 10+ candies and 10k+ dust to raise to CP by 21 or so? IMO the value of high CP mon plummeted when the gym system changed. Before an extra power up may have been enough to bump you up in your gym which kept you in longer. Now with FIFO it doesn't matter.
Yeah the diminishing returns past level 30 are fierce. Some people have done the work to find the breakpoints where the expense actually makes a difference, but you can probably take a critter from level 20 to 30 for about as much as it takes to go from 30 to a relevant breakpoint.
This works pretty well for figuring out the damage breakpoints: https://dominikzen.com/pgo/attack-pro/ And no, there's really no reason to have more than 6 maxed out attackers of single type. Duoable T4 bosses (Tyranitar and Charizard) require only 6 and Tyranitar is doable with 3, if one manages to revive them and return to the battle fast enough. If speaking of Golem specifically, they are currently only usable for duoing Charizard and soloing Flareon (if one gets lucky). However they are also potentially very usable for Ho-Oh in the future.
Don't see a whole lot to get excited about. Porygon/Magneton are nice for hoarding candy if we look ahead to Gen4. I could see Golem being useful to players who don't commonly find geodudes. It's a new bunch of lvl 3s to try and solo if you're into that. Not sure if the previous raid bosses are being phased out of if they will stay. Seems to be they are being phased out. Raid timers also down to 45min.
Really looks like they drew names out of a hat for these. Metapod?