What do you like best?
I am using CacheFly CDN service for many years for our professional blog and other websites. Their origin pull is very good service. The sub user account, real time hits, FTP access, easy setup of origin pull CDN are the features which definitely reasons one should be happy to use. Users can use just FTP credentials in CMS like WordPress to integrate CacheFly CDN - there is no new learning of proprietary API. It is easy and does the job.
What do you dislike?
Cachefly is actually costly CDN. However, options for CDN with good performance is very less particularly when budget is not crossing $50/month. The web GUI is not exactly grade for the cost - it is simply designed for the work.If they had OpenStack Swift backend, it would possibly help the developers more.
Recommendations to others considering the product
If you get Cachefly's pay as you go plan, there is nothing to look back than opening an account. They do not change the existing user's plan.
What business problems are you solving with the product? What benefits have you realized?
Obviously a CDN intended to serve the static contents as fast as the main dedicated server and decrease the load. Biggest advantages of Cachefly is FTP integration and easy origin pull CDN. Users can easily create a separate sub account for storing the content and separate account to mirror the whole site.