#1
I'm looking to pickup either a Seymour Duncan JB or an El Diablo for Metal as well as Paramore style rock. Would the El Diablo be worth the extra money or would the JB have plenty of output for the style I am going for? I wouldn't mind saving the extra money but I don't know of the JB is a good metal pickup though I know Zacky from Avenged Sevenfold uses a JB.
#2
The difference in output is minimal. The tone will be very different though. With the El Diablo you're looking at blades and alnico 2 magnets so the tone will have a lot more mids. That's going to hit your amp hard. Great if you have a good low gain tube amp and you want maximum distortion without having to use an overdrive pedal but it's going to suck when you try and get any kind of cleaner tone. The JB has regular pole pieces and an alnico 5 magnet and a slightly cooler wind. But still very hot by regular standards. So that will have tighter bass and more cutting treble but won't drive a low-gain amp as hard.

If you have a high gain amp the difference in output won't be noticable since your amp will be capable of heavy distortion already. If you have a solid state amp then the output won't matter because solid states just don't work the same way.

The JB can do metal. Some really bassy guitars are better off using a ceramic magnet pickup like the Custom or Disortion but for most guitars the JB is a solid high-output choice. The main advantage of the JB is it's capable of softer tones too, at least better than most 'metal' pickups are.
The El Diablo should be able to do metal well with the right kind of guitar and amp but it'll be very easy for it to sound very muddy and I would never trust any alnico 2 pickup to do really heavy metal. And the huge output and the blade style magnets mean it's never going ot be quite so good for softer styles either. Quality wise the SD custom shop is no better than regular SDs, the custom shop models are only called that and cost more because they're less common winds. They're still made by the same people in the same way using the same parts as the other SD pickups.

For metal I'd almost always take a SD Custom, Distortion, Alternative 8 or one of DiMarzio's many high output ceramic pickups. For 'Paramore style rock' I'd take something more basic like a Pearly Gates or '59 model. The JB is inbetween the two. If you definitely play one style more than the other then think about getting a more specialised pickup. If you play both styles equally, the JB should be what you want.
#3
Ok. Thank you for all of the information! I'm really into the metal scene but noticed that I've been playing rock a lot more lately. I think I am going to go with a JB in the bridge and a '59 in the neck because I've been wanting just a little more mids as well as the versatility to play the clean sections without any tough of overdrive. I think I am going to head to Guitar Center and see what they have for guitars with a JB and see how they sound and probably order them pretty soon. Thanks for the information again!