Edoardo Maggio/Business Insider Samsung has officially unveiled its newest flagship smartphones, the Galaxy S9 and Galaxy S9+. Business Insider attended the company's press conference in Barcelona, and got some time to spend hands-on with both devices. The S9 and S9+ will go on sale March 16, but customers will be able to pre-order it this Friday (March 2). Here are the key takeaways you should know about if you are considering buying either phone:The design has remained virtually unchanged. Edoardo Maggio/Business Insider The first thing that's immediately noticeable upon picking up a Galaxy S9 or Galaxy S9+ is just how similar they are to their predecessors. The same 5.8- and 6.2-inch displays (for the S9 and S9+ respectively) dominate the devices' front; an aluminum strip goes around the edges, and a glass back shimmers. If you didn't notice the different positioning of the fingerprint sensor — which now comfortably sits below the camera, and not next to it — or stumbled upon one of the new colours, like the "Lilac Purple," you would really have a hard time telling a Galaxy S9 and its predecessor apart. Samsung's new phone seems a lot like the "s" versions of the iPhones in years past — but that's not to say that the design has any noticeable flaws.