>>96506370
As I understand it, the largest of NEXT are stretching to around 12 meters tall (not counting psychotic boss-monster prototypes), if I'm not mistaken that puts an Atlas's head at their shoulder, but I'll admit BT scale discussion is an exercise in futility. They're still unbelievably fast at their size compared to Battlemechs, if only on account of taking G-force limits as a challenge and having enough booster power to spit on any sensible thrust-weight ratio.
Anyways, the cores from other games and 'normals' in 4 and FA are probably ballpark similar to Battlemechs; though slamming a lot of engine and a lot more jets on than most mechwarriors would ever consider practical.
Behold: An AC.