There are many Free Zones, Mainland company you can have anywhere. Which Free Zone to choose depends on what you do and what location and budget do you prefer.
There may be 15-20 Free Zones if not more, and each has its specifics. They differ by location and pricing. The way how you think about whether you need a Free Zone or a Mainland company is by nature of your intended business. If you want to do business in UAE, physical or online, you need a Mainland company.
If you want to do business outside UAE, e-commerce Amazon store with customers outside UAE or consulting then a Free Zone company will be a fit.
There is cheap labor, if you produce some goods you may consider moving your factory to UAE and benefiting from labor. If you import goods, there is 5% tax, but some products are exempt like medical or other products.
The license costs (the price you pay to do business) per year vary and are normally higher for Mainland companies. Also you own a Mainland company to 51% while 49% is with a UAE national. Free Zone is 100% ownership.
With a Free Zone, you can have an office only in that Zone. This means you need to make sure you like the surrounding, if you plan to come here to stay, before choosing.
You may also be appointed as a CEO and stay in your home country – very practical and tax friendly.
In terms of money, expect the lowest price for a Free Zone license (which is located not in a comfortable place) to be around €1,500 and for a Mainland (can be anywhere, no attachment to a location) can go up to €8,000 per year. This is with no office space.