What does the company do well? I love that it is very simple to use Optimizely for simpler test and that it provides a great engine for splitting up your traffic for more envolved test. Using the smart editor I can set up tests quickly and without any help from engineering which speeds up our testing cycle significantly.
What does the company not do well? Pricing is rather steep, especially if you want access to some of the more advanced features such as custom goals and location targeting. Optimizely also only help you test without a developer on smaller changes (this, however, is a problem with all solutions that I'm aware of).
What about the company do you wish you had known before purchasing? Not really anything. We did a lot of research and used the product on a free plan initially to see how it performed. The lack of support might be the only thing.