I find that the front page is really lacking for upsource. I never use the favorite projects links and there is a ton of wasted space.
It would be nice to have sections for reviews I am the owner of, reviewer, and watcher. Easily visible so I can click onto each one. Currently my workflow is slowed down as I have to look at the news feed or go over to reviews which is a page that is much to loud and hard to track down the relevant information. I just want to get to a review as quick as possible. I don't need all the information in the world.
The actual reviewing UI is really good. Don't see any needs for changes there. It's just really frustrating to have to put forth so much effort just to get to a code review.