What do you like best?
Great uptime, generally responsive support, good pricing, strong hosting control panel.
What do you dislike?
Sometimes their techs are unfamiliar with the finer aspects of ExpressionEngine, a CMS they support.
Recommendations to others considering the product
It's a no-brainer unless you have high capacity/bandwidth needs (1M hits/day, video hosting, etc). In that case, do your research.
What business problems are you solving with the product? What benefits have you realized?
Nexcess has been our go-to host for several years. Their relatively quick setup, full-featured hosting control panel and SSH allows us to deploy websites with minimal hassle.