There are a few different soleplate coatings for irons. These include ceramic, stainless steel and titanium.
Stainless steel is definitely the most common. It’s non-corrosive and heat resistant, making it ideal for ironing. However, things can stick to the stainless steel which can leave marks on the clothes.
Ceramic coatings work well, too. They can eliminate static at high heats, but they can also wear and tear more over time.
A titanium coating is great for fast ironing, an even transfer of heat and its ability to resist material particles from sticking to it. At extremely high heats, titanium soleplates can melt materials.
Each coating is best for different things, so you should consider your personal circumstances before choosing.
For a general guide, choose stainless steel if you iron natural fibres like cotton, rayon, wool, silk and linen. If you iron a lot of synthetic clothes such as spandex, use a ceramic coating. If you iron both frequently, try out a titanium coating as it works with pretty much any fabric.
If you do go for the common stainless steel, just make sure to clean it often so it doesn’t leave unsightly marks on your lovely clothes.