Exactly as described, I see no reason to buy a used VFD when you can get a brand-new one for less.
I wouldn't call a VFD "easy to use", it's a technical tool. The manual gives you all the details you need.
Still, if you have never set up a 3-phase motor, you're going to need to do some research.
If money was not an object, I'd still buy this VFD. (thinking of buying another)