The one thing I disliked about the AC series was that often the differences between one weapon and the next was almost indistinguishable. Your uber-rockets-of-death are equal in strength to his laser-of-despair.
The differences between different types and grades of weapons was more substantial in the Mechwarrior series.
I played AC 2 and 3 and sure, they were mech games, but they were pretty bad.
The difficulty curve throughout the game fluctuates from mildly easy to excruciatingly hard, and in AC3 in particular you were limited to ammo-less lasers because using anything else ammo-based would bankrupt you within the 4 first missions. As for strategy of mechs and how to build them, there really wasn't any. You had no choice but to go with the heavy type since anything else would get blown to bits in five seconds of entering into combat. The only exception was when missions were on an obnoxious timer where you needed a light mech to speed through, and those missions were near impossible even with all the best gear you could get to that point.
I tried completing both games but I got stuck on missions that were brutal and had to find a guide. When you need a guide to just finish a loving game's regular storyline there's something wrong, either you're playing a JRPG or a really bad game. Not saying AC isn't "cool", almost any game with mechs gets cool points automatically. It's just the gameplay of the early games are simply terrible, maybe the new games make up for it but I dunno.