I voted Championships. It was a hard decision. During the championships I was a little more concentrated. But because the regionals are the first competitions of the year, to me they are a little more nerve-wrecking. By the time you get to nationals you are used to the surrondings(music, crowd, etc.). When you get to Einstein it is back to or over the nerve level of regionals again.
Both are a lot of fun and it is great to be around all the robots and competion.
