Correct me if I'm in the minority here but when I'm at my computer (desktop or laptop) I've got my left hand at the keyboard and my right hand in the mouse. It's pretty trivial for me to type a keyboard shortcut and hang on to my mouse at the same time.
Keyboard shortcuts will always be superior for one reason: consistency. Every computer you will ever sit down at will have a keyboard with the same buttons in the same places and a 2 - 3 button mouse. Because I've learned the shortcuts for Windows and Mac I'll be productive no matter what you set me down in front of.
Now imagine I set myself up with a Brand X super duper mouse, invested a lot of time in configuring my shortcuts on both keyboard and mouse then I work there for an extended period and get real used to it. Now for whatever reason I end up somewhere where I don't have my awesome personalized configuration and Ultimate Mouse (TM). At this point I lose all $6,000 worth of those "productivity gains" either reconfiguring the system or retraining myself to remember the defaults. The way I see it, there's a fine line between just enough customization and overkill for the sake of productivity. I'm always for learning the defaults plus a few tweaks if needed that way your "productivity" is always portable.
Maybe I'm out of line though. It just strikes me as odd that someone would write about their mouse and mention a very specific one at that. This just came off to me like product placement under the guise of productivity tips. If I'm wrong then I'm sorry. Sorry that I made the implication, not that it came off that way to me.