And if you want to play around with Practiscore on your own, you don't need to buy a Nook or anything if you already have an Android or iPhone. You can download and install the PS app on either of those (it is free) and work with it anytime you like.
We've been using PS at ENGC for USPSA, Steel Challenge, and Multigun for quite awhile, and we've used PS at Sectional and Area matches for the last several years. We love it. In local matches, by the time people have the stages torn down and put away, we have the results finished and can print them out. You can run it with a range LAN, or a portable battery-powered router, but even without that if you have someone with an Android phone who can set it up as a local hotspot, that'll work too. (That's how some folks get copies of their scores when we go to lunch after matches, when they can't wait the extra hour for it to be uploaded to Practiscore's website and to the USPSA website.)
For matches, using Nooks is by FAR the best idea---long battery life, and you can read the screen in bright sunlight. Also, comparatively cheap. For personal use, your phone works perfectly well. I know some people who go to major matches, set up the match stages on their phone, and enter their stage times/points into it to check their scores as the match goes on. (To make sure the reported HF matches their official score---mistakes do happen.)
If you run matches, you can set yourself up on the PS website as a club, run registration, and pull all that registration directly into your device without having to type it all in. After the match, uploading the results to PS is literally a click of a button. Uploading to USPSA to IDPA takes not much more.
Good stuff.