There might be more support with Arnold. Certainly more documentation at this stage. I'd suggest vray or Arnold over prman.

hey, it's quite difficult to say really if there is no reference to compare thing to. To me it looks like some of the objects are out of proportion.
I'm not really a fan of the lighting either. I...

Hey most of this is looking great! How about working on the lighting? It's quite flat right now.

What scale is everything?

oh really?

it's great! How do you find it?

do an RGB ID/Matte pass.
http://www.9jcg.com/tutorials/neoscape/rendering_mattes/large/rendering_mattes_03.jpg

or maybe output only one channel from the new render layer you made.

hey I think this needs more model detail. The panel stuff looks like a bump map.

which image type are you rendering?

hey what you want to try and do is not have any of the creases or lighting baked into the texture. You have a detailed texture on a simple mesh here. I would work on
-some displacement maps (sculpt...