I've only had Busy Being Blue for a couple of years, but it seems to be a good bloomer. It is one of my earliest iris, which I like.
I've grown Neptune's Cloak for many years. It is a good increaser and reliable bloomer.
I only got this last year, but it bloomed in a pot, which I thought is a good sign.
All three of these are as close to true blue as you'll find in an iris, IMO.
