The 60 series is a benchmark in handheld units.
I've had both the 60csx and the montana so i'm not guessing.
Real buttons are nice. They are tactile and you know when you press it even without looking. The touch screen requires your attention much more. The 60 is very small and compact. It works well off the bike too. If you were doing allot of off bike work with a gps, the 60 is hard to beat.
What i do like about the montana is the way it generally works. It is fast. Easy to input, big screen, and the ability to load many maps at the same time makes this a deal maker.
Wiping dust from the screen is a pain. Setting those damn pins is annoying, but those annoyances make the tradeoff worth every pennny. I'm sticking to the montana.
"Build a man a fire and he will be warm for the night, set a man on fire and he will be warm for the rest of his life."