Remembering there's no such thing as a free lunch, anyone could be surprised by what stands on WebCEO's (one of the top SEO software developers) website: "Free version: No time limitations. No nag screens. Yours for free for ever."

However, the free WebCEO version is indeed free. You are even getting 3 months of updates for functions and for search engines with it (though any tools from SEO PowerSuite, for example, have 6-month and lifetime offers respectively).

No nag screens? That's also almost 100% true in WebCEO. That's right - some of us hate screens saying "Sorry, you didn't pay for this so you're not getting it. Or how about paying?" In WebCEO, you won't see too many screens like this. Instead, many functions are simply inactive, mostly because they're limited by the free WebCEO version: http://www.link-assistant.com/webceo.html.

But where there aren't any nag screens, you end up scratching your head. Because you don't see the familiar "Please pay to us" message, WebCEO keeps you wondering, if it's a software limitation, or you'd just need to go and change something in settings.

The free WebCEO restricts competitor research to almost a nought, allows only 5 words for keyword research and puts strict limits on abilities to analyze.

From the restricted version, you can still make restricted reports. They will have WebCEO logo and their foreword, so they're only for your own use.

SEO PowerSuite has a different approach. The free edition of SEO PowerSuite tools won't let you pull all data from main view into reports. That means, you can't show reports to anyone and hold them in your hands printed out. But unlike WebCEO, SEO PowerSuite will never limit your ability to optimize your site. You can research any number of words, check any number of sites and analyze as much data as you need - you'll get all necessary info without restrictions and will be able to use it immediately.

Besides, despite the promises, in WebCEO you will see some nag screens asking you to purch the paid version.

But all right, let's give credit to the guys - sure they need to make sale. Here's where you'll find a detailed comparison of WebCEO and alternative SEO tools: http://www.link-assistant.com/web-ceo.html.