I bought Sabine Baur 3 years ago and it didn't bloom the first year. Last year I had a few blooms which failed to open properly and a few that were blotchy. I decided to give it one more year and look what happened!
Given that we have had so much rain and lower temperatures than usual, also that a lot of my plants were decimated by gall midge SB has clumped up nicely and I had a lot of good blooms. No re-bloom yet though and not the colours you would expect to get with more warmth. The jury's still out at the moment but I will definitely give her another year.