I've been browsing the Nokia developer forums, and there is definitely a lot of panic and anger going on. I'm sure internal developers are feeling similar. A lot of them feel that Nokia shouldn't give up on Symbian or MeeGo. Finland is very proud of Nokia, and to have them adopt an OS that wasn't home grown feels very wrong.
This is a big change. A lot of the things that these people have been working on for the past year or so will soon be thrown out the window. That has to be pretty tough to swallow.
A lot of these workers may be out of a job soon. While Symbian is being kept around for another year or so, there isn't going to be any further development on the platform itself. And the MeeGo team is going to be cut down significantly.
There will be people that see it as an opportunity to learn and grow. There will also be people who see it as a betrayal. Both of those reactions are understandable. The former will help a person bounce back faster than the latter.
I wish them all luck.