I have had great experiences with young and older sp's and I have had poor experiences with both also. It is not age that determines the quality of an sp. There are a lot of factors; experience, attitude, chemistry, mood etc.
My experience is that each sp manages this in their own way. I have never felt it to be uncomfortable and somehow I have always known without looking at a clock when it was time to exit.
just pay attention. You will know.
I had the extreme pleasure of seeing Effie a couple months ago during a visit to Toronto and she is high on my ATF list.
I agree the appropriate review of Effie is WOW!