It is some brand of Wilbar, all steel. I looked at one assembled at the poolstore and was comfortable with the side supports.
A round pool will always be less expensive than an oval if it's at all possible you can get a better pool for the same mony in round than oval.
Some excavation will always be required - to remove existing lawn and level undisturbed soil. It may look flat but it almost never is unless you've measured it level