So, you want to use a machete, champ? That's great! Just like your old pop!
I'm already sick of this shtick, so here's the info.
A few things to know:
-machetes ARE NOT light weapons; they do not get the dex ap reduction
-straight machetes have a tighter damage range (especially a higher low end) and slightly higher crit chance, but lower crit damage (usually by 20%)
-curved machetes have a wider damage range (a slightly higher max, but a much lower low)
-as usual, tichrome machetes have 1 less AP cost (most melee weapons have 1 less AP with tichrome; machetes have 2), tungsten ones do more damage/have higher crit bonus/higher str requirement, etc
-the main strength of machetes comes from your feats (and through them, specializations)
You want Flurry. You also want onslaught. Decapitation is nice but not vital. You also want Ripper; not vital but boy it's nice. Get expose weakness if you know what is good for you. I would also get cheap shots, critical power, and any crit-chance boosting feats.
Flurry is your bread and butter. It costs 35 ap to use, makes three separate attacks; if any of those attacks miss, the flurry ends immediately and goes on cooldown for a several rounds. The ap cost is 35 regardless of what kind of machete you're using or what you're wearing; so it's best to use a heavier one (and you dont even need tabis!). Each hit of a flurry lowers the ap cost of the next flurry by 4 (which stacks up to 5 times for a 20 point reduction). There is a specialization to lower the AP cost by up to 5 points, and another to reduce the cooldown. You can get flurries as low as 10 ap if you can keep them up; you always want the highest to-hit percentage you can get.
Flurry goes very well with onslaught. Onslaught increases the damage of following attacks every time you land an attack, by 5% and stacks up to TWENTY times (and you can up to double the bonus with specialization points), but like flurry, if you miss even once, you lose all of it (no cooldown though). Sit and think about the math for a moment; let it sink in. Now imagine that you had the highest crit chance you can get, as well as ripper, opportunist, cheap shots + critical power....
Yeah. Have fun, but be careful, if you miss on a flurry in the middle of a dangerous battle, you might be effed. Have a plan B, and a plan C, and it helps to have a lot of move points, or the stasis ability, or morphine, or a forcefield, or whatever makes the most sense for your build.
Be careful when making your character; tungsten machetes need 6 strength, decapitation needs 7 strength, dex affects crit chance, you need 5 will for ripper, 5 int for cheap shots/expose weakness, 6 int for weaponsmith, and you'll probably want sprint at least which requires 6 agi. Good luck; I've had a lot of fun with mine, especially later in the game.