Fullhand is alot more comfortable. Typical wrist rests can't be used as the ergodox is a little awkward used on a flat surface, which is why most users (afaik) tent the keyboard. If you tent a classic, having no wristrest makes it rather tiring to float your hands all the time.
Do check out what kurplop has done with his here; effectively he still provides a place for resting his wrists using the tray.
http://geekhack.org/index.php?topic=43709.0Search for Glod's - ah, nm, I'll quote it from elsewhere:
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A classic case, that ultimately is put together like the fullhand using a custom made dock. Unless you're planning to travel with the ergodox alot or willing to create a custom solution, I think most users would be better served using the fullhand case, unless you're going to use the keyboard flat (and no, you really shouldn't).
A fullhand, tented; one of my older pictures
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A video of a fullhand in action;
TLDR; get the fullhand pls. Unless its meant for travel, or you're gonna build one of those wonderful custom jobs linked above.