What is Nand? Fresh has its own OTA update kind of thing right? Does fresh support flash? What made you choose fresh over DC?
<Notice: This is all from an amateur hobbyist, I just got my Evo last Tuesday and was running the stock OTA all week until it was rooted Monday around midnight, I'm still learning. But I am an electrical engineer and fairly tech savvy, so may be falsely confident about my understanding of this stuff>
I dunno how accurate this description is. In general NAND is a type of flash memory often used because it is non-volatile(sp?), pretty quick, and inexpensive compared to other memory technologies. I just say this so you aren't confused if you hear about NAND in something else.
In relation to the phone, I think its used to store all of the settings, application data, etc. To be able to read/write to it readily after unlocking (via Toast's part 2) makes backing up and restoring stuff much much much easier. As far as Fresh goes, I believe you have to have NAND w/r access or else when you flash it, it will go into a reboot loop forever and never load. If you do flash Fresh, expect at least one reboot loop, this is part of flashing and loading this ROM.
If you can load into recovery (hold volume down and power, then wait for it to finish its scans for files, then select Recovery.... or just reboot into recovery from ROM Manager or 'adb reboot recovery') then can do a nandroid->backup and then a restore you are fine.
Flash? I haven't tried. I can try when I get home, although I'm sure someone can answer that before I do. I don't have much of a need for flash on my phone, but I believe it may run Flash 10.1 lite. As I said, Don't know for sure.
Fresh vs DC: It was purely a matter of convienence and opinion. People I talked to on here and xda seemed to recommend Fresh more for a user like me who isn't huge into trouble shooting. I got my exposure to adb and flashing, but I'm still new to it. Fresh seems to work out of the box with 4G, camera, etc, so I'm satisfied at the moment. I haven't run into any problem.
Fresh Updater: Haven't used it yet to update a ROM, but I assume that is it's purpose. As new ROM versions are put out, it would be easier to flash using his util. It also allows you to flash in cool themes quickly and easily like Rosie's Rotating home screen, vanilla lock screen (w or w/o vanilla clock or weather, etc), and other stuff.