It's easy to track your own stats because you have access to your logs, server info, etc. Keeping track of what the other marketers in your niche are doing isn't quite so easy, unless, of course, you use the correct niche marketing tool.
A truly flexible and informative niche marketing tool gives you options on what exact facet of your business you want to analyze. To illustrate, let's assume that both you and your competitor have sites with different product pages. A good tool will allow you to enter a specific URL from your own site and compare it against a specific URL from your competitor's, as well as the basic homepage comparison.
Why is this important? Because search engines analyze websites page by page. By optimizing certain specific pages on your site, along with your homepage, you can get two listing in the search results. By having two listings in the top ten, you effectively push one of your rivals out of the race, and double your changes of getting traffic. Why wouldn't you want to do that?
One final point: the user interface is crucial. If the information you need is spread out in a labyrinth of numbers and percentages, then it doesn't do you much good. When looking for a niche marketing tool, you not only need one with a wide range of features, but also a program that is able to present the data culled from those features in a worthwhile way.
The ability to download a free trail really comes in handy - see if the product delivers on its promises. If the information you need isn't presented in a user-friendly way, then what good is it to you? The reason for getting a niche marketing tool is to make your job easier, not more complicated.
Staying on top of your competition means being aware of what they are doing - and ensuring you do it better.