This will depend largely on where you plan to install the floor, how long you plan to be in the home, how much wear the floor will get and how much you want to spend.

The main advantage of solid hardwood floors is that they can be refinished many times, making them a good long-term investment. But they are not suitable for installation in basements or over concrete slabs, which usually admit moisture from the soil.

Engineered hardwood floors can be installed over cement and in basements because they are made of multiple layers of wood laid perpendicular to one another, which makes them more stable than solid planks. Engineered woods are generally more affordable than solid hardwood floors. Their chief drawback is that they cannot be refinished as many times as solid wood.
Hardwood floors are relatively easy to clean and maintain, which makes them a pet-friendly choice. They are vulnerable to scratching from your pets’ nails, however. Keeping your pets’ nails trimmed can help prevent scratching, and using throw rugs in key areas can also protect your hardwood floors from pet damage. Choosing a harder species of wood may also help prevent scratching and other pet damage. It is also important to consider your personal tolerance for scratching and wear when choosing your flooring.
Installing solid hardwood floors is a difficult project, requiring advanced do-it-yourself skills. Installing engineered hardwood floors is a bit easier. Proper installation requires making sure your subfloor is properly prepared and level, centering the floor and laying it out properly, working around features, doorways and trim, leaving enough room for expansion and contraction of the wood, and possibly moisture testing. Someone with advanced construction skills may be able to manage a good installation, but if you are unsure, it is best to leave this job to the professionals.
The three main considerations for choosing the type of wood are price, hardness and appearance. Woods vary dramatically in price, so your budget is a major deciding factor. Once you’ve established your price range, consider the amount of wear your floor will get. If you have pets or children and expect your floors to see a lot of traffic and use, you may want to choose a harder species of wood. Beyond that, it comes down to which floor you find most beautiful. The options are nearly endless.
For solid hardwood, you need a solid, level subfloor made of plywood or other wood. For engineered hardwood, you need a level wood floor or concrete floor with appropriate moisture levels. To check whether your concrete floor is suitable, you will need to have a moisture test done.