I've been using Keyshot for maybe one year. Keyshot is very easy to use, and very fast.
I like Keyshot over Photoview 360 because it render faster, and I think the finale "product" look nicer in Keyshot. Photoview got more preset materials, but it's very easy in Keyshot to edit material to your liking. Keyshot is also as simple to use as Photoview 360.
I would recommend trying Keyshot. They have this trial that you can use.