as far as speed and dexterity learning marching licks is a great idea and a nice way to clean up some of your strokes
those players are extremely strict as far as technique, stick height, and dynamics
everything is under a microscope and expected to be a certain way every single time
so it could be beneficial to any drummer to try to play with the discipline of a rudimental player but a set player should be quite a bit more loose in his technique and his feel
I was a bit obsessed with learning a lot of these pieces about a year ago and found it extremely difficult to match the rigid feel of guys like this ...this is one of the many pieces I learned and I took a lot from it
http://www.youtube.com/watch?v=60ZXvYLGS7M
i recommend checking out this site to see whats going on in the marching snare world ...its quite interesting and competitive
http://www.snarescience.com/index.php
but as far as what to learn on kit snare
learn to seamlessly combine rudiments and have them flow together nicely with tasteful dynamics
I recommend Pat Petrillos book Hands Grooves and Fills
Pat presents awesome solos built of rudiment combinations written in a very easy to understand short hand that will get your hands used to some really nice flowing combinations