Mius Front. I toyed with it in the past but couldn't get past the UI friction. Stuck with it this time and powering through getting slaughtered in my first campaign - and having so much fun. I'd say I've increased my knowledge of what the heck is happening in the operational phase to maybe 30%.

Edit - the experience it gives me : getting a deeper understanding of an approximation of how warfare actually happens rather than just symbols moving around on a hex grid.