Re: P90s Vs Humbuckers
A good vintage PAF sounds just like a good vintage P90 does with the tone control rolled off a bit.
Now having said that more modern versions of both tend to be a bit middier and muddier, but can be in the same ball-park. My preference is for P90s, and I use a load of effects. I think of the humbuckers as being pasteurised P90s - cleaned up - but having lost something in the process.
The drawbacks of P90s are more hum and background noise, and a generally gnarlier sound. I don't think of them as much as drawbacks as opportunities for guitar obscenity and hooliganism.
Might turn out not to be for you, but you haven't lived until you've tried them. And FWIW they're probably my favourite thing...