I've seen some performance issues when synchronizing a large number of feeds. Basically it's going out to each server and downloading each feed. Google has a way to do this more efficiently, but I've only briefly looked into it. After this first bug fix release (version 1.2.3), I'll have more time to take a look.
There was one fix in v1.2.3 that might cause an error and freeze the UI. Once the release is posted would you mind trying it out again? It had to do with missing data in an article.
Version 1.2.3 should appear in the App World shortly. This is my first patch after the official release, so I'm not sure what RIM's timeline is like for updates. Stay tuned.
Thanks,
Jason