I've been tempted to try one of the Kensington offerings (one of my Logitechs has a dying button and I'll need to replace it soon) - have you tried the expert m

I've been tempted to try one of the Kensington offerings (one of my Logitechs has a dying button and I'll need to replace it soon) - have you tried the expert mouse or the slim blade? How do they compare to the Logitech?