keith,
can't really offer any advice as to which would be better. I've got a steel workbench set aside for the lathes when I get to actually setting up the "machine shop corner" part of the shop (number 10, 11, and 13 on the list right now). 3/8" top with storage compartments underneath. If your interested I could snap a few pictures/grab a few measurements for ya. It's still sitting outside right now so I won't have to move anything to get a good picture.
-Aaron @ the SCF