Like the 1000+ hours i spent in game, can attest Battletech is a "top value" game. This was my first introduction to "battletech" and the campaign does a good job of easing you into the universe. Some lore videos later (mainly Tex), a couple of novels and the only way to trully experience "battletech" is with mods. Any one of the three major mods (Rogue Tech, BT Advanced, or Commander) will do (based on preference and/or hardware :) ). Just be advised the unity engine does it's usual memory leak "feature" so a restart of the game around the 3h mark to avoid crashes is advised.
The game is made by the same studio who went on to make War Thunder and in some ways it feels like a stepping stone to that game. It looks great, the soundtrack seems properly awesome, the plane library seems to cover all the major planes found on the western front (none from the pacific though - as far as i can tell). For two euros i'd say it's a must buy if you have any sort of interest in flight games.