What do you like best?
I mostly like Vultr for their low entry prices and the abundance of data centers, making it easy to get a VPN close your location (or your customers').
What do you dislike?
Once you deactivate the DDOS protection, you cannot activate it again (unless you contact their support center and ask them to do it). Seems like "trick" to make sure you don't only get the DDOS protection for few hours/days.
I'd understand if they would charge and lock it for 1 month, but if you cancel it then you can (in theory) never activate it again.
Recommendations to others considering the product
Look for a coupon online and try it for free, you will be impressed with the performance and results. If you want to manage websites with it, I recommend Runcloud.io
What business problems are you solving with the product? What benefits have you realized?
Cheap and fast cloud hosting. I use it both for both managed (Cloudways) and unmanaged (Runcloud.io) hosting.
The prices are better than shared hosting, you get better control and overall better performance.