I like it and it is a very good tool. But I mainly focus on small businesses, and I often find SEMRush a bit expensive. Plus, I do SEO and not SEM, and I'd pay less for a plan with SEO tools only. I recommend to do a trial first: the keyword and page analysis are amazing and I think they are really helpful when it comes to optimize every page of a website. Plus, SEMRush competitive analysis allows you to compare the SEO/SEM/domain strenght etc. performances of several websites of your choice, so that you can take action and improve your rankings.
Spy On Competitors’ Best Performing PLAs: Which of the competitions’ product listing advertisements are showing up the most on Google? What do the ads look like, well that’s where this tool can help. The PLA Copies report shows you copies of the competitions’ advertisements via Google’s Shopping. You’ll see each ad as well as the number of keywords that bring up those ads in Google Shopping Results. This allows you to pick up the top performing ads used by the competition, analyze how they work, and you’ll know what Google prefers the most and then use them for yourself. The tool’s filters allow you to sort data by Product Price or Product Title. Plus, you can narrow the search to ads that are relevant to your business. Also, all reports can be exported in CSV, XLS and CSV formats.
SEMRush is one of the best solutions I have found for discovering site errors, getting a great explanation on how to fix it, and even posting for social media. It covers end to end so many of the varied areas of SEO, that it's become an invaluable part of my business. My favorite has been utilizing the ranking tools to see how we compare against competitors, and also tips on getting featured snippets (which we achieved for one client this year!)
Monitor Changes in Statistics: The Display Advertising Feature also allows you to see the changes in statics which depend on the ads and the devices on which they are displayed. Your display campaign will be visible across tablets, PCs, smartphones, etc. All of which results in being able to see which devices are producing the most impressions, check if text ads are doing better than media ads or vice versa and adjust your campaign settings to allow for better interaction.
The tool also helps you discover and follow the hottest topics in your niche via the nifty hashtag reports. You can see which hashtags are making posts more engaging and take a peek at what your competitors are doing. Plus, it allows you to see who has mentioned you, your brand or products with a comprehensive “Mentions” report. The report also helps you discover PR opportunities.