Their design is just fantastic - especially with the latest update which added better Stations support. When it was first released it was wicked snappy and kind of slowed way down for a while and got annoying - agreed.
In the past month or two, though, it's gotten damn responsive (for me at least). Give it another shot if you haven't used it recently.
Actually, you're right! It's the same picture, scaled down to around 500x500 and with a heavy gaussian blur applied to it. The trick is to have a subtle grain effect over it to eliminate gradient artifacts.