I have discovered this fantastic free tool called SpyFu, which provides a wealth of information about any competitor’s website even before you join in.
1.How much do they spend on Google ads?
2. Which of their Google ads have generated the most clicks?
3. What is its organic reach?
4.What are the best links to their site?
Our members have also suggested that these services investigate even further into the data:
SEO and ads analysis: SemRush and SerpStat
Traffic: SimilarWeb
Backlinks: aHrefs
Social networks: BuzzSumo
Source: www.spyfu.com