What do you like best?
It's really easy for google made indispensable software and services. Google Docs its one of them. Why? Because it allows, in a completely free way, to:
Download files in a variety of formats, auto-save documents to your Google account, has an simple and versatile interface, share your documents or keep them private in a simple and immediate way, automatically identifies spelling errors, embedded chat application makes it easy to collaborate.
So, what more do you want for a free service?
What do you dislike?
For use it you must have Google Account (who dont have one nowadays?), work only online, doesn't have advanced editing tools, typical of word processor, sometimes file format and layout its changed
Recommendations to others considering the product
There are many benefits in use Google Doc service, yes I still use Microsoft Word in 80% of cases but if there are documents I need to share for work or with family then Google Docs is the way to go.
What business problems are you solving with the product? What benefits have you realized?
Fast document editor, easy way of share it and collaborate with other team. In our society we use it even for simple note. With online editor, we reduced costs due to a license of traditional word processor and increase productivity thanks of collaborative nature of the service.