What do you like best?
It connects with Google Analytics right off the bat. It's free for an unlimited amount of views like Google Analytics. It's by Google which means its more or less trustworthy and will be around for a while. It also has a great web editor built-in that allows you to make changes to your website and publish from inside the Google Optimize software. That is pretty awesome. And the editor works with wordpress cms as well, to my surprise.
What do you dislike?
Google Optimize, like Google Analytics, don't have exactly the most intuitive user experience/user interface. It's also relatively new and still ironing out the kinks and the bugs. The instruction for installing it onto my website is also not the clearest, and I had to look up clarifications to the instructions. Also according to documentation, it still doesn't work super well with Google Tag Manager yet. It's relatively new though so that can be forgiven. It is limited to 3 experiments running at the same time which is disappointing. For small sites, that is more than enough, but for large sites with large numbers of views per day, that isn't so great. Support like all Google free products is pretty much non existent, they just tell you to use the help forum.
Recommendations to others considering the product
It's a free software so why not try it. However, it's like Google Analytics, not exactly the easiest to use. And unlike Google Analytics, it hasn't been around for a while so there aren't many tutorials on it. If you don't have many views on your website, I would try using the free tiers on Optimizely or other A/B test competitors. However, if you do have more views than those free tiers allow for, give Google Optimize a shot.
What business problems are you solving with the product? What benefits have you realized?
A/B testing websites and launching multi-variant experiments.