What do you like best?
I just wanted to give a quick foreword, I'm not super proficient at Linux/Unix-like OS'es, but I have used Ubuntu Desktop and Server OS multiple times but my comfort zone is Windows. That being said, Ubuntu has by far been the best Linux Distribution for me to learn, test, and develop on. In my opinion, I feel like where Ubuntu shines is it's strong community support. If you are new to Linux or even new to computing, administrating, networking, etc... Ubuntu is probably the best place to start. The Desktop OS provides an incredibly intuitive design that allows people to get moving quickly while still allowing total systems control like a proper OS should.
For the Ubuntu Server OS variant, I personally learned almost everything I know about Linux on Ubuntu so transitioning to the Server OS was a cakewalk.
What do you dislike?
I think the largest dislike for me when learning and transitioning to Ubuntu was that the majority of OS management was performed at the terminal. In the Server version it's performed strictly at the terminal. When i was first learning my way around Linux I was having a hard time with getting SSH setup so I could log into the server remotely. I found tutorials online but they always seemed to be missing a step or two and I couldn't seem to get it to work. Finally, I asked on a Ubuntu Support forum and the community helped me get SSH setup, with an SSH keypair (certificate instead of password), and took the time to explain how SSH works in Linux. Primarily being a Windows user at that time, the entire setup and configuration was completely foreign to me.
Recommendations to others considering the product
If you are looking for a robust, yet stable Linux OS with tons of free community support then Ubuntu is the right choice for you. It seems to have some of the best hardware driver support out there so if you are installing on a computer with bluetooth of WiFi capabilities then Ubuntu will probably be the best experience with working drivers out-of-the-box.
What business problems are you solving with the product? What benefits have you realized?
I'm currently using Ubuntu as the OS for my development environment of a MEAN stack web app. I'm also running Ubuntu for my DevOps management node while I'm learning Ansible. (Ansible doesn't currently support Windows being a management node.) I'm running web servers with Nginx, Tomcat, Apache on them, Back-end MySQL and MongoDB databases.