I personally consider myself to be a marketing strategist but one of the things that I always tell my clients is that I don't work magic and as such I don't work on search engine optimization. I help make sites rank better through other initiatives, but I don't tell them that they are going to rank higher, just because... it actually takes a bit of effort in order to make that happen.
Have you used any SEO services in the past that have actually worked for you? What ones are horrible? Lets make an SEO good guy and bad guy list.
Most SEO companies are made by one person who has outsourced staff from other countries. SEO directory listings are popular nowadays and actually does work but it's hard to justify 1000 directory links in 24 hours or so even splitting the work into several people. I would get frustrated in doing this sort of work so they must use some sort of tactic to do it. I personally wouldn't go for it, even if it was 100 links for $1 - I'd rather submit links to directories myself and save myself a few quid.
SEO would bring great results for sure. But it’s not an overnight miracle.
It requires a lot of time of patience.
While you consider whether to go with an SEO, you may want to do some research on the industry. Google is one way to do that, of course. You might also seek out a few of the cautionary tales that have appeared in the press.
While Google doesn't comment on specific companies, we've encountered firms calling themselves SEOs who follow practices that are clearly beyond the pale of accepted business behavior. Be careful.