Well I only looked at it over lunch, but I saw nothing that seemed to faze it (and I went through most of the standard apps, plus a few "extras" my friend had installed) and pretty much all the gestures seemed fluid and intuitive from what I could see - in fact I don't recall seeing any pop up menus for example, the UI is incredibly finger friendly.
They do say a fool and his money are easily parted! There's no reason why Nokia cannot provide fast application startup, a unified UI *AND* an open platform - if the UI falls apart due to community developers not following the Nokia UI standard, that isn't Nokias fault. The devices as they comes out of the box should be able to satisfy all of my requirements - if Apple can do it, Nokia should be up to the job too. So far they have only demonstrated they are not - you'd think the OS 2007 Hildon UI is from the Jurassic era when compared side-by-side with that of the iPhone. OS 2007? Maybe it should be OS 1997, or even OS 1987...
If the UI is designed correctly, I don't see why there should be any reason for conflict. The current OS 2007 UI - as it comes out-of-the-box - falls far short of being a consistent UI, it's as if Nokia forgot to write a style guide (or worse, didn't enforce it), and the situation only becomes worse as more Nokia approved applications (Skype, Video Center, FM Radio, Media Streamer) are installed as they're all different with their own little widgets, themes and means of control and navigation.