I changed from the old shape 650S to a 1000S about a month ago, I had the 650 for about a year and a half and done 10,000 miles on it after doing several long weekends on it I decided that a bigger bike was needed. Decided to have a test ride on a 1000 enjoyed it its not as chuckaboutable as the 650 but still loads of fun with similar engine characteristics.
A change I don't regret.