[Jason.]

BB6/BB7.
I think BB7 edges it, as I loved the yellow and red lighting, that series, which made the set look nice. I liked the diagonal walkways attached to the stage, which gave Davina more room to move around.
The crowds were great that year, too.

BB8 was good. I loved the long walkway, and the multi-coloured lighting, which fitted with the eye very well.

I agree with Lostie!
BB15 had the best looking graphics and lighting which made the exterior nicer.

In all fairness, the C5 set looks better now than it did in 2011 and 2012.
It's the same, but I like the lighting and graphics these days.
Twisted Fairytale also looked nice.