From what I have seen, the monocarpic ones like Semps and Aeoniums do that center blooming which is the start of its end, unless it is able to make new babies before it goes.
But so far the Echeverias just keeps going and going, makes buds & blooms, or after the bloom then pups on the bloom stalks after the bloom fades. And mother plant still stays okay, actually seeing it form a big caudex, to support all the life it continues to give. I just cut the bloom stalk if it really starts to go brown, and brittle, but otherwise, still fresh green, it will continue blooming or make pups on that stalk.
Here is an example of my Echeveria 'Paul Bunyan' has been blooming on and off since August 2013. I like that it has made a new plant on the bloom stalk, and at the same time baby plant is likewise in bloom..really hard working mommy plant.
Photo last June 2014
Photo 24July2014
mommy plant
and the babies/blooms
So pretty much it will be a matter of aesthetics...maybe if you want to keep it in just one rosette cluster, then you may want to cut off the bloom stalks. But for my own preference, I like to see them grow any which it wants.
