Directory Submission Services - Are they worth it?

We recently undertook a project to provide SEO to a companies website. The owner was getting around 50 hits a week and he wasn't happy. The site is a telecommunications site which services the North Wales/North West area of the UK and its quite a competitive market so we thought that it would be reasonable to add the site to as many directories as possible for 2 reasons.

1) Provides back links to the site, which as we know, increased the page ranking because google See's the site as a better resource.

2) Business directories are always well used, its free advertising and the more you are on, the more change there is of someone looking at that directory for your company.

Now submitting to thousands of these sites would take myself and my colleagues ages. So long in fact that it would cost the client an absolute fortune. Because of this, we decided to enlist the services of a third party company called Directory Maximizer who, for a minimal fee per listing, will submit your site to these directories. They will even handle the final submission email for you as well so you don't need to worry about this.

In our experience, this saved us a lot of time but the pages were slow to be indexed and linked back to the customer. So far, we have submitted to over 1000 directories but have only got around 52 links back from them so around 5%. It's not a bad return and they will increase over time so that's not an issue. The customers happy as well because we can give them a list of sites which they have been submitted too and they can go and see the results for themselves.

From an SEO point of view, would I use this service again? Possibly, it saves myself lots of time and meant we got the information onto those directories for a minimal cost. Being so cheap as well it's also cost effective to get listed. The 5% return doesn't sound like a vast figure but when you consider it took 10 minutes to sign up to the service it is a fair return.

So, on my next projected, if it's a business user and they want a massive insertion into directories then yes I will use the service, if it's a small projected it might be better to target the ones required to maintain quality.