Dean,
I purchased Drill Draw this year, and I think it's quite good. At the start of the year I was good about entering drills and making complete practices, but as time went on I found it more useful to print out index card sized pieces of paper just to keep me on time between drills.
I think the major benefits of drilldraw are that it's easy to learn, it's a great way to archive and organize all your materials, and you don't need an Internet connection. There is a great tutorial that shows it's features here:
I was leaning towards the TC whiteboard program at first because I liked it's simplicity, but they switched to an online version that relies on the Microsoft Silverlight plug-in to work and I had terrible problems with it working.
Hope this helps….
Dave