Conclusion to this part: The first app contain 16 functions and it's free. It worth to be tested through there are only 35 reviews. SEO doesn't show you results within 7 or 14 days of trial. I want to say if you're a beginner, try a free app not to waste a penny. When you know what exactly you need (for instance, fast page speed load, rich snippet, image resizer, or all together), you will be able to select the exact app for your purposes.