Well I'm the odd man out, I hated the McKeesh. They were a good mirror when on & adjusted. They are bulky, they lose adjustment when the are off, they take a fair amount of storage space when off, they have to be re-tightened when it starts to rain & the straps get wet, the strap is nasty to store wet and they could not be adjusted so that they wouldn't mar the paint in the door sill of my Sierra. Oh yeah, they're expensive too.
When I got the extendable mirrors on my new truck I was surprised first trip out that my wife said "I sure won't miss those other mirrors you had to have". I guess I wasn't the only one tired of dealing with the McKeesh.