HKS filters will fall to bits over time, they have a pretty short lifespan in them before the shroom needs replaced. They do make pretty good gains but its at the cost of filtration. They filter like crap, and since most cars use a hot wire MAF this can become a big (and expensive) problem.
K&N are pretty good, but after cleaning them you have to re-oil the filter, again oil going onto a hot ickle wire is also a bad thing. Although K&N post some pretty good gains.
Blitzquickshift or any filter that uses a metal mesh tend to be crap. Good power gains, crap filtration. Dust and crap that doesn't get trhough tends to block up the filter resulting in a 'dead' area of filter, which kind of defeats the purpose. They are however, oil less and very easy to clean, ie take off car run a hose through them and clean with compressed air to force water out.
Pipercross have serious issues with build quality, ie they are probably the worst filter I've had the misfortune to use.
Green are quite good, slightly below K&N with similar pros and cons.
Apexi are by far the best, best power, best noise, best build quality, a 'dry' filter cone (ie no oil). Just the best, con is getting them to fit your application often resulting in custom jobs.
The more I try various filters, cone or panel or even box filters. The more I think its a big marketing gimic. Believe it or not, the restriction of an OE setup is not the paper filter, its actually the box, cold air feed or the rest of the intake. Fix these and you are sorted, plus you save money and can just chuck your cheap OE filter away when you want.
Induction kits are normally bought for the noise more than anything else, I believe, unless properl thought out and installed they are a waste of money. Maybe good on the stage or track but for town driving probably a bad idea.
Just my shillings worth mind .