The problem was it was after BB1, 2, and 3 which alot of people love and considered the best. BB4 came along and didn't live up to the previous series expectations. The, to make it look even worse again it was sqaushed behind BB5 and BB6. It was produced well, there were a few massive twists, but just not the right housemates or living conditions
Still, better than the series 8 unwatchable monstrosity.