This is a subjective question.
Now look, I understand real estate formulas and all that, but in the end, what it comes down to is the end product, and what it cost you to produce that end product.
The 2 important ideas for you to think about are
1 the cost of building on the site. If you have a hugely slanted slope it can cost tens of thousands in civil works/retaining walls and all that jazz.
2 design the building so that it complements the site. I know of many marina estate sites that slope down towards the rear of the property, where the water is. They put the living areas at the back, overlooking the water. That completely upends the frontage rule of having the property looking great on the streetscape, because we have multi million properties doing the opposite! and maximising their amenity.
Now, getting back to reduced elevation properties - dont think that having a downwards facing property is a bad thing. It is often the opposite. Having a property with a steep driveway can often give you a great deal of privacy, because no one can look over into your land. One of my cousins properties is like this - you go down a steepish driveway, but when you get into the yard/living, you feel like youre in your own private world.
So what it really comes down to is what youd like to do, what you would like to create etc for whatever reason. But the point blank thing that I will say to you based on my experience as a builder/developer is to go with the site. Dont change the site to suit your idea. If you want something flat, buy a block that is flat. If you want something staggered, buy a block that is staggered. Dont fight the site. Use it for what its good for, or buy something else that suits your idea better. Change the site, to suit your idea, by buying a better site in the first place. Earthworks are unneccessary unless you just love the site and want to live there eventually. In that case, good luck to you. But its a bad developing decision. Youre just adding obstacles/pain.
Whatever you do good luck, but as usual, be a complete financial athiest. make decisions based on fact, and money. When emotion gets involved, or if youre hell bent to develop that site...thats when you get problems. 5 figure problems.