Can't speak to the time question, though. How good are you? And how fast?
Illustrator has powerful 3D ability and people do manage photographic-like quality in illustrator vector files... which is amazing. And of course you can link up Illustrator output and Illustrator 3D output with Photoshop and that can give excellent results.
But I can't really answer your question. Depends on you. And usually anything worth doing well takes time.
I will say that it's quite amazing what can be done with a dedicated 3D package. So far, I've worked with a number of lesser 3D programs and can get some nice stuff, but I'm currently way sold on Maxon Cinema 4D.
But there are folds doing the Illustrator/Photoshop dimensional work that looks stellar.