It really depends on what your objectives are? If your objectives are to increased traffic then adding content to your blog is a far better option.

**Benefits of adding content to your website **

• Long tail keywords = lots of traffic

• Possibility of links (if you provide great content, it could get links. Don't expect to get lots easily though, check out this question I asked about blog posts and links acquisition ratio's)

• Permanent asset for traffic and links.

Benefits of Guest Blogging

• One guaranteed link

• Networking with other bloggers

-Bring some traffic from other sites that might have lots of traffic.

If you’re going to guest blog ensure to choose a website that has a massive user base of traffic. That wouldn't be achievable if you added it to your blog.

Alittle of topic but FYI, It's free atm to add your blog to botw Blogs http://blogs.botw.org/

So if you have a blog, add it. I added mine and get listed within a few months.

They also have strict submission criteria which means they are still a quality directory.

Firstly how long have you been waiting? You can expect waiting times of up to 6 months or more.

Secondly it’s possible a competitor is the editor for that directory but pretty unlikely, it more likely they have a big back log. Or they don't have an editor / active one for that section.  You can always try and apply for the editor position yourself (although I've had no luck with this).

DMOZ can be a really powerful link, but it really depends on the section you are trying to get, and how many other listings are already there.

I would submit once and then forget about it and focus on content creation and other areas. Add yourself to BOTW and dir.yahoo.com.

Never hear of these “Submission services” but they sound like waste of money and time.