I watched a bit of it, it looks fine, the only problem was frame rate dropping at climbing the windows, must be to do with too much detail to render, details that you can't see from that distance anyway so I think that could be a simple fix if they replace the texture on the windows or something. Other bits looked okay to me, I saw no characters flying or walking under the city. There was some pop ups, but nothing too drastic.
Yeah it all seemed pretty good to be honest and the only real bad bit was at the windows. I was laughing at that point so jumped around a little bit there while talking to my brother on skype. Although It did make me chuckle when I got a story part my stream went from 6 viewers to none in about 5 seconds.
The only time I have really noticed pop in was when I was actually looking for it but during the day to day gameplay I never noticed it.