The "roller coaster" effects in the 3-d view are my favorite. They've got some smoothing algorithm going, or it wouldn't curve the way it does, but the elevation data must not have a high enough resolution. Google has made this sort of thing look so easy for so long, but it's clearly very hard to get this stuff right. So, I guess it's not that surprising that apple messed up something incredibly hard in their first a…
I also wonder how common these problems are. I live in San Diego and everything looks pretty-good to me. It renders my house in 3D and the turn-by-turn navigation worked great. There are obviously problems in some places, but so-far-so-good here.
There's definitely room for a lot of improvement …