IMHO - here's the deal.
I watched your video trailer Lanny.
I think your TomTom will work fine from keeping you getting lost - if that is what you need it for. Can happen to anyone out of their own enviorment.
If you want to track yourself on GR3 radar on your laptop - to know where you are relative to the storm cells - then the DeLorme may be the best. If you don't use GR3 or level 3 data/radar interpreting programs; then TomTom is all you will ever need. Hey, It can resond to voice and give voice instructions - great!
I haven't bought or used the Microsoft puck - but I have heard/read chasers saying they were happy with it. Honestly - that's second hand info. I don't know how well it runs on applications like GR3 - and I don't know how many applications it can run (GR3, SpotterNetwork, its own map program, and/or more) or if it has issues w/Vista. I do know that it cost more than DeLorme. Maybe someone who owns the microsoft unit can jump in here and tell their side - that would be great too.
For the reason of cost, efficiency, and expectations - and the fact that the DeLorme LT-20/Earthmate will run out-of-the-box on a laptop w/Windows Xp - I chose the DeLorme unit from eBay for $40 plus S&H. When set up as directed with the Serial Port Emulator, it works first time every time after laptop startup. You need to plug in the puck, then start the laptop with no obstruction to the puck from the sky. Put the puck on the dash and forget about it. Best $50 spent on chasing gear - bang for buck.
I've gotten lost only a couple of times when chasing in unfamiliar territory. I then start the DeLorme Street Atlas and find out exactly where I am. Otherwise, I just use the Serial Port Emulator that will start automatically in startup - then open GR3 and start GPS. (It isn't necessary to run the Street Atlas for it to work - just be sure the Serial Port Emulator is in your startup file in programs. Use default setting - they work for me anyway.) Blink - on goes the little white bullseye/GR3. Done. Then I start the SpotterNetwork Client software, and then I am off to the chase. Over a dozen chases after I bought it and hooked it up - great. No problem...
I use Windows Xp exclusively, if you use Vista or other O/S's - your mileage will definitely vary. If Vista; then the Franson GPS Gate is a must. Seen/heard too many people complain that Vista has issues with GPS gear. I recoomend DeLorme because other experienced, more knowledgeable chasers (Mike H & Amos M) than myself (a rookie) gave me the nod for the DeLorme. They were not wrong..
IMHO...