The problem with these sets, despite all the positive calculating is that in time they become obsolete. Manufactories continually upgrade, which event buildings do not. I know you're gonna say, well the Royal Restoration spell, but I'm fairly sure we're in for a nasty surprise with that. The other option, I suppose, is to be constantly upgrading your sets every time a new event comes around. In order to keep updating you would have to be happy putting anything into your city without being fussy, no matter what it looks like.
Me, I haven't used any snowflakes yet. The one building I'm going to go for is "Fishing Spot" as this is the one building this time last year which I felt was sufficiently not snowy for it to make it into my city, so this year I will just be replacing that with a higher level version. Aside from that there's nothing I want. I am looking forward to getting a bunch of instants, but I am hoping that once... just once... there is a day where they offer something generic like time boosters or something, but they're not going to do it are they?