Yes, FSX Steam is the best version of FSX you can get right now with FSX Gold features and some improvements for modern systems.
But keep in mind that some addons designed for FSX Gold won't work well/doesn't work with FSX Steam, FS Recorder 2.x is one, which just crashes FSX Steam on startup with it just refuses the current version of FSX (simconnect to be exact). For that, you've to use FS Recorder v1.331, but even that has warnings for incompatibility at startup.