What do you like best?
The customer service response times for critical issues has been incredibly helpful and almost every time nearly immediate when requested.
Toolbox of "extras", for example other companies and the tools they have available for Acquia customers to use has been helpful. New Relic is a good example of this.
What do you dislike?
The caching times for our larger multisite have sometimes been an issue without implementing force purging, which has helped some, but not always.
There are at times unclear or incomplete instructions for non-critical support tickets. Being directed to documentation that I have already found on the site, but was not clear enough for me to fix the issues myself is not helpful.
Recommendations to others considering the product
Depending on the needs of your business and frankly the size, Acquia can be a huge reassurance for hosting when things go wrong or support is needed. The Drupal community as a whole is also a great resource. I do not have experience with single site installations on Acquia, but I have heard from colleagues of good experience with that as well and good price points.
What business problems are you solving with the product? What benefits have you realized?
Hosting with a company that is well versed in Drupal - our main platform - has been a huge problem solved for us. Our previous hosting is not knowledgable with the Drupal CMS, so there were times while hosting on our VM on their server we would run into configuration issues that are now a non-issue because Drupal is all Acquia focuses on.
Immediate security updates from Remote Administration has solved any issues as far as security breaches and the window in which the potential for anything to go wrong might.