I think Zbrush is about the same price as Photoshop. I think it was around $550. If you want to texture your models in any other program you probably will need a copy of photoshop along with a copy of that program but with z brush you can texture your models efficiently inside of the program. The only downfall to z brush is that it doesnt have any animation capabillities. I dont know how Z brush compares to Amphorium because ive never used it. Zbrush is the closest thing to modeling out of real clay that i found out there which makes making impressive 3d models really fast. Unlike other 3d programs where you mostly pull and push verticies to shape your model. Plus it has a very powerfull displacement mapping system that makes a very very low poly model look like it is over a million polys. One more thing to blab on about Zbrush is that Weta Digital (Lord of the Rings makers) are using zbrush to make all of their 3d models now. One example is the King of the Dead in the last movie plus a lot of the orc characters. So yes, Zbrush is a tad expensive but whell worth the price in my opinion. Best 500 that ive ever spent on a program.