Sig campaigns are overrated, people mostly want them as a source of income and post count boosting. Don't believe the hype 
It is true that people are trying to earn from it. But is that a bad thing to do? After all signatures are serving their purpose and advertisement is visible for everyone on bitcointalk.I still think that this is the best option to advertise here, Op can also purchase official bitcointalk banners but I think signature campaigns ads are still more noticeable.