Intuition is for noobies (I love it :p), but Cateye is a very good build. works well.
I also tried marines with EE instead of MAc, and it's great too.
In all cases, a nuclear or nanomachic plasma/laser rifle will be your best friend, but they are not necessary at all (and it seems all good players will prefer antigrav boots over a nanomachic weapon)
My personnal choice is to alternate with the use of a shotgun (usually, normal or tactical. I don't like 7d3 ones), which has a great ammo efficiency and is always reliable. I hate playing without a shotgun anyway, it makes pain elemental expensive, and sometimes dangerous.
the ammo consumption rate looks ridiculous
That's only true for the plasma gun !
I rarely use a chaingun, but it's quite effective, and you always find tons of bullets.
Also, if you never tried it, craft a gatling gun ! I prefer using my B-mods on nanomachic weapon, tactical RL or BFG, but it's a cheap and effective gun : you won't have the same ammo problems, and the damages are equal to a plasma gun (well, bullet damages still suck a little, and don't divide armor, but it's not that bad)