What do you like best?
What can you say about word press themes. if you are not as savvy with the design niche then themes are for you. Personally i don't think the basic non creative or technical user should be using themes. I believe that a theme or a template is a foundation to the creative outlet of that person and their ideas. and honestly many only use what is right in front of them.
What do you dislike?
it feels kinda of dirty using a template or a theme for web design as it is a flow of artistic design by another. Much like using someone else's underwear. You just don't do it.
Recommendations to others considering the product
My recommendation is that if you use word press themes to change them enough to be unique to your company and idea
What business problems are you solving with the product? What benefits have you realized?
I'm Not really solving any problems. I have clients that are cheap and believe in a certain set of beliefs and do not like to spend money investing in something that makes them money. So in these cases i use themes.