Ali, I have never used SEO services and I am not sure I will. It takes a lot of time, effort and money to sustain search engine positions.
While we know what the benefits can be, think of potential cons:
- if the person managing the SEO process isn't experienced, he might overlook certain rules that might ban your site from a search engine altogether;
- once you get in top 20 or top 10 listings, it will take a lot of time and money to sustain your position;
A lot of times content and relationship building with strong resources is what really pays off. I would personally rather invest in text-link advertising that is located on serious pages like InfoWorld or ZDNet (or smaller but quality tech resources) rather than spending same hundreds of dollars on something that might not last you even a few months.
Best,