Looking for jobs through an agency or not?

I have recently started to doubt the profit of looking for jobs through an agency. I mean, it will be much more expensive for a company to hire me through an agency than if I applied by myself.


Good parts

+ They help me find vacancies.
+ They handle salary negotiation for me.
+ They can push for a quicker response without me getting shit for it.
+ They are very nice and good at spreading buzz about me.


Bad parts

- It will cost more for the company to hire me.
- Sometimes the agency's personnel is incompetent and might ruin your chances.
- They put forward a lot of people and of course always says good things about them, which makes them lose credibility. I mean, it's their job to get their candidates hired. They will say anything to make that happen.


Summary

I think that if you already have a good contact net and know a lot of companies, try to contact them yourself instead of using an agency. If you are fairly bad at finding jobs or negotiate a salary for instance, you might benefit from using an agency.

The choice is yours!