I'm not very fond of the SH-upgradable-buildings. They're a bit big and fugly even in their lower level skins, they don't really suit my SF, and most of all they have absolutely nothing to do with the Simpsons. It's like they've escaped from some other game, taken illegal residence, only to multiply like a virus.
That's not to say that people haven't made some awesome designs with them, although of what I've seen in neighboureeno towns most just lump them in a pile somewhere for the hidden XP.
I suppose that it does give something to do between events, but I've already reached billionaire so there's even less point for me to get ten of the latest Exclusive Resorts.
I was hoping that the next stage of SH would've come with some actual Springfield Height shops like Abercrombie & Rich, Get Your Picture on a Rembrandt, The Prodigy Barn, Victors Secret, and Things Unnecessary (picked these from Wookiees great post on tstoaddicts). For future up-dates and events here's hoping they keep it in the Simpsons universe and make the game-play less tedious.