The most common grid based game I have played would be PBI. Grids discreetly marked on a cloth by dots or small crosses on the corners of each square.
I spent over a decade running a school club, there were a lot of arguments over ranges/movement with non-grid based games plus the perennial question of "is he in cover from here?". Try umpiring for a dozen teenage boys for an hour, and you might find grids more appealing.
I introduced them to PBI and within a few weeks nearly everyone had taken it up. Arguments largely vanished. No measuring needed, just count the squares. If there is any terrain in the square you are in cover, if not you are in the open. The only potential for arguments now is over things like cocked dice. We also adopted a policy of being fairly figure agnostic so long as they were based and recognisable, so although I used 15mm metals, some of the players went for 10mm from Pendraken, others used Airfix plastics. Likewise support vehicles were in a mix of scales (in one case a player with Airfix plastic infantry picked up a couple of Pendraken anti-tank guns as support). Not all figure bases were square, some figures were just based on pieces of cardboard box that had been cut into vaguely geometric shapes with a pair of kitchen scissors. But the games were enjoyable and far less fractious.
So there are pros and cons