Think about the moisture level where you live. Solid wood will cup if you live in a high moisture area, especially if your subfloor has gaps. True, engineered floors have a thin layer of veneer, their finishes are baked on at the factory and are much longer-lasting than finishes applied on-site. I'd consider solid wood if it's pre-finished because of this fact. Plus no dust in the job site and you're in and out quicker.
Another tip I just learned -- if you're in a high moisture area, you can follow all the manufacturer's installation instructions, and if the floor cups and the customer calls out the manufacturer to inspect, they will still find it "100% installer error". After follwing every instruction by the manufacturer, they came back at me asking if I tested the moisture content of the subfloor and if I sealed the subfloor. And where was that in the instructions?
So after tearing out the floor (for free), I caulked every seam in the subfloor and am using a subfloor sealer which guarantees the wood floor installed for the life of the floor. Yup, I believe that one too. Now I get to install the floor for free as well.