Well...when I build an array that has a large quantity of spindles, I tend to test the very-likely scenario of a drive replacement before actually putting data on it. I may also be biased and conditioned to things like this being in the enterprise storage industry.
FWIW, the rebuild completed successfully without incident. It took 14hours and 30 seconds to complete. I used the machine normally during that time so it's possible that my playing media files from it may have slowed it slightly.