I guess it depends on how much time you have. You could dig a pond with a shovel and wheelbarrow.
Personally, I'd rather rent a track loader or dozer.
I am not sure which is more efficient for moving dirt. I find that a track loader is easier to dig with. A dozer is harder to keep a level work area (maybe it is just me).
An operator can do more in an hour than you in 2 days? I doubt that. I suspect they may be more efficient but when I can rent a loader for $50 per hour but it costs $80+ for a contractor, I suspect I can save money driving it myself, not to mention why should I pay someone else to have all the fun?
Now, they normally leave a prettier work area than I. I beleive it is because I quit too soon. If I was getting paid $80 per hour, I'd probably spend an extra 2 hours smoothing/packing the dam face, too.
They are dangerous, take your time, do not get in a hurry. If you get in trouble, quit and get some expert advice.
I have some steep dam faces. Personally, I let the experts work on them.
