Terran units ride the middle ground between Protoss and Zerg. There’s a lot to consider, and all three possible matchups (TvT, TvZ, TvP) can play very differently from each other.
Also, in compositions that make heavy use of the Barracks units (also known as “bio” units), players will need to make sure that they are creating the correct balance of Marines, Medics, and in some cases Firebats. In a lot of matchups, Terrans will need to make heavy use of Siege Tanks, Vultures, and other Factory units (also known as “mech” units) that need to be controlled very carefully, and strategically. That said, while Terran can be a great choice to play, that shouldn’t be your reasoning since Terran can be just as complicated, if not more so, than the other two playable races: Zerg and Protoss.
Things like tanks, marines, medics, flamethrowers are all things that most people can figure out how they work. The Terran race might be initially appealing to casual RTS players and/or first timers because their units are very recognizable due to them being grounded in traditional human technology. Terran is one of the three playable races in StarCraft: Remastered, an enhanced version of the original StarCraft and its Broodwar expansion. Terran Beginner Basics, Builds, and Tips & Tricks for StarCraft: Remastered