I had a bad experience with a large SEO company and fortunately got my money back that I paid in advance but it was a nightmare. I don't want to bad mouth the company because they did refund my money in full.
My biggest issue with local SEO companies is that they are probably doing the same thing for your competition. So where is the advantage????
If you go with a big company that is not local, you run the risk of poor customer service (my issue).
So I decided to check out programs that I could operate myself. I am currently evaluating AWR at the enterprise level but they have a great personal website package for $99 (Standard edition). You can go to
http://www.advancedwebranking.com/ to check out all the features.
this site will review the Top 10 - http://seo-software-review.toptenreviews.com/advanced-web-ranking-review.html
Great software or a company that offers SEO service needs to be able to analyze the algorithms that Google and the rest are constantly changing. This software does that and does not cost an arm and a leg to maintain a current presence. You can add an algorithm package at a small price compared to other programs that make you get a subscription at a pretty hefty monthly fee.
The best part is that you can try it out without any charge for 30 days. It is a full service trial for that 30 days.
If you don't like just don't buy it!
Here is another review of AWR - Pros & Cons that is well organized. http://www.poweredbysearch.com/advanced-web-ranking-ultimate-review/#awrExcludePlaces
If you decide to farm out SEO - make sure you cover the concern about your competitive advantage. Remember that many companies offer website building and a full array of services. The more services your competition has with this company the better their SEO will be over your website!