Well, people have had bad experiences with both Dotpocket and Nyditot and have been very vocal about them. I tried Dotpocket and it was very unstable for me. It would freeze up, requiring a soft reset, and once, gave me a blank screen, so I removed it. Nyditot Virtual Display was much more stable, although they give you a warning to backup your device in the event a hard reset is necessary (not very reassuring, but apparently a real-world possibility), everything went smoothly and it appears to be very stable and useful. Your mileage may vary.
You're right in that with a new unit, you can load either, play with it, and if a hard reset is necessary, you won't have much data to lose.
You can get Nyditot at
http://www.nyditot.com
Best of luck,
Ron