This was a damn good event for me
Before, water spawns weren't all that common and I never saw Shellder, Omanyte, or Seel spawns beyond some recent (much needed) nests in my area. With the festival, I got dozens of Karp, Psyducks, Tentacools, and the rest.
The biggest standout by far is the cp970 Omanyte with tier 1 IVs.
The biggest disappointment is a tie between a garbage Lapras spawn (the only one for the entire event!!11!) and a cp648 Totodile with meh IVs (Which I'm still keeping because reasons ...).
I could've caught so many more Karp, but between my internship, school, and other commitments, 260 candies is all I could muster. But it 260 less kilometers I have to walk for my 2nd Gyarados, so that's a net profit there.
Edit: Mass transferred out 90 Karp, now have 3 with tier I IVs.