I did psychology in my first year as an outside option so can help you a little bit.
The department is very friendly and there is a real community feel to the building.
The course is accredited with the BPS which is critical as I'm sure you know.
I didn't actually enjoy the first year course very much but most that I know really liked it. You do sections from all areas of psychology so really get a flavor for the subject. Tutorials are very much presentation based and you also have to do 10 hours of research participation during the year.
Feedback on essays isn't brilliant.
Oh and on the BBB entry requirements, most that I know had got straight A's at Alevel but Edinburgh do take the personal statement seriously as well.