Does look nice. I should get me some land with a pond. That way I don't have to build one.
Building your own pond is like building your own house. It's a blast, but a major pain when you make mistakes -- and you will make mistakes.
Still, I don't regret it, despite the cost of money, time, and energy. There's something special about catching (and eating) your own fish, watching your project bring joy to kids, and experiencing fellowship with folks you invite.
That all said, it is simpler & cheaper to buy an already existing place. You may well have to kill what's in there, though, and remake the lake.