I own a host of spotting scopes, including both mentioned by the OP.
The Vortex 20x60x80 DB is very nice for the money. I've had no problems spotting deer and other game at distances way the heck out there.
The Leupold Vantana 20x60x80 is also some nice glass, but I honestly don't think it is any better than the Vortex DB, as good, but not cleaner or brighter imaging IMO, and my vision is very poor, so I require decent glass.
I also have a very old Bushnell, and even though it's not water proof, and fogs really easy, it does do a good job at extended distances to the ability of 30x.
And unfortunately, I also own a Leupold 15x45 something or another. I honestly don't know which model it is, cause I only used it once or twice before retiring it, it's nothing but a piece of junk. The only thingit has going for it, is that it's water / fog proof I think? I have a $50 Winchester that is about the same quality as the Leupold I spent $300 for, which is also junk.
GS