That's quite odd as my opinion is quite the opposite, I've found it a Godsend for speed in 3D modelling able to go to extreme detail with ease, so much more ease than your bog-standard 3D modeller, okay my PC isn't able to go into the millions of polygons due to a lack of ram, but it has made 3D modelling feel limitless, stress free and has taken out some of the complications I have had with your standard modeller.
As for photoshop, I've seen people easily interact with it between Zbrush, although I feel I wouldn't need photoshop to paint my textures as I can do it in Zbrush (Only playing with the demo I wouldn't have that advantage) and as for Maya, I wouldn't know how well its pipeline with that is, but I know a lot of people can use it with 3DStudio Max with little trouble.
As for the price? Whats wrong with £300 for a 3D modelling tool that can now go into billions of polygons with little effort to render, that can render for illustrations, that can do allsort with high detail and ease.
As for corel - how do you compare corel painter and Zbrush? Zbrush is a cross between 2D painting and 3D modelling, Corel Painter is 2D Painting...if you were going to compare Zbrush, I'd use Blender's scultor, Hexagon 2, Modo, Mudbox or Silo 2. If you're doing that please rule out Hexagon and Blender - Blender isn't very articulate for the same purposes as Zbrush and Hexagon is buggy.
Look behind you a threeheaded monkey!
