My dynasty is in Twinbrook, and at week 33, it still runs decently well on my laptop and loads in 10-15 minutes. My file is currently massive, though, at a hefty 919 MB. I honestly don't know how it still manages to run well. And I blame my file size on my own bad habits of building big and traveling often, rather than anything related to Twinbrook itself.
I've heard great things about Lucky Palms' performance, too.