Recommendations to others considering Arnold:
I would compare Arnold to other major renderers, especially in terms of being able to render using the GPU and not CPU renderers Review collected by and hosted on G2.com.
What problems is Arnold solving and how is that benefiting you?
Arnold helps me create photo-realistic product renders as well as environments. The benefits of Arnold are that it's a good, cheap alternative to Maya Hardware and Maya Software as it comes built in to Autodesk Maya when you purchase it. It's pretty easy to learn how to use (at least, the basics are) and any issues that you have, you can find the answers in the forums and in YouTube videos Review collected by and hosted on G2.com.