each yeast offers subtle differences in flavor and body of the finished product. we all have our preferences. i make only dry mead, so i only use wine yeast, but even that is a large field to choose from.
alcohol tolerance is the biggest thing to decide, then flavor.
my favorite yeasts for mead are
favorite for cysers are
d-47 (careful with ferm temps on this one though)
and nottingham (if you treat it right, it doesn't have a problem going up to 11%)