If you're in the market for a rapid fire controller I will say that before you drop $100+ on a controller please do your research and don't simply take the word of 1 forum or site. A lot of gaming forums are sponsored by rapid fire companies and the moderators are paid to make sure only good things are said about them.
I own 2 evil controllers, 1 master mod and the other stealth adjustable, and I must say they are awesome......at first. After playing with them for a while you soon realize the rapid fire is 8 times out of 10 slower than others rapid fires you encounter during online play and yes I have adjusted the sps(shots-per-second) numerous times. The build quality of evil controllers is great and you can tell they really take their time in assembling these. Are they built to last? Yes as long as you're not one of those gamers who throw your controller down or slam it against the nearest hard object.
If you're wanting the best of the best and plan on dropping $250-$300 on evil controller let me stop you right there. because you are limited to what the mod has and can only use the controller mod on first person shooters Evil and just about every other rapid fire will not be worth it. VikingDigital's Macro controller will be your best bet hands down, the controller has a record feature that can record ANY combination of button,stick,trigger presses and play it back on the fly or you can edit the recorded macro on your computer. To make things even better VikingDigital has a macro database that has a ton of current macro's for MW3, BlackOps, GoW3, and even Madden games so even if you don't feel like making your own macros you can grab one from there.
Now if you don't want to spend $250+ on a controller but still want the best go with a Arbiter 3 rapid fire controller. The Arbiter 3 from Modiify is considered to be the world's fastest rapid fire and has over 70 modes which include Drop shot, jump shot, rapid fire, auto run, burst mode, LT Cancellation, fast reload, dual trigger, auto aim(offline only), and Ultra fire aka Jitter mod. For full list of features check out the manual here I will be getting rid of my evil controllers and getting one of these soon so once I receive it I can comment on build quality and customer service.