Really this topic has been brought up too many times already. Mechanics actually have really good dps and out damage genetics in terms of aoe. And they just need STR for it whereas genetics need INT as well. There are no defense sacrifices either as you can wear a shield with pile bunker and also have a slotted garment with raydric or deviling. Rangers can't use shields or garment reductions and also don't have energy coat like mages.
Mechanics also have one of the highest hp pools in the game:
http://irowiki.org/wiki/Max_HP (updated with post balance hp values)
madomechs are a dif subject. axe mech is a completely broken abandoned by gravity classbuild which is insane considering how broken the mado mech suits are. basically as a whole mechanics are just broken all around
as for mado mechs:
pile bunker is the hardest weapon in the game to get, only second to the bio4 make it yourself monster drops. that -_- is absolutely STUPID to make/get. they need to implement either a better system for getting Brocca's, or come out with a set for mechanics to use that works as well as pile bunker.
that said, arm cannon is a cool spell despite its longer than cart cannon cast time but the SP cost is absolute insanity considering the SP pool that mechanics get, and often results in a tremendous waste of SP items to be able to level/play at a reasonable pace or long long long periods of sitting waiting for SP to regenerate and if you run out of SP midfight, youre left completely crippled. this is a huge problem for the class.
the mado suit is -_- as a whole. requiring players to carry gas AND cannonballs for every attack you do is stupid and a waste of weight capacity. and have you ever tried using arm cannon without a pile bunker? it does mediocre as hell dmg. the majority of players wont be able to get a pile bunker due to its rarity and price, so that leaves people with using genetic weapons to attack with which dont scale well at all. and finally theres the fact that you lose your suit on death and have to go back to prontera to rent a new one. what the hell kind of bs system is that. a genetic or ranger dies on an ET run they just get ressed and keep fighting. a mechanic dies on ET run and he has to go back to pront to get a new suit. completely not fair.
/rant