looking for 3d engine

Hi all

I am looking for a 3d engine to do a visual system for a traffic
scenario simulator. We will be using a COTS traffic model and I want
to be able to integrate the visual system fast, through an easy API.
One should easily be able to load the world and vehicles. One should
also easily be able to navigate cameras and vehicles in the scene.
We will not be using a lot of cool effects, so that is not important
in our choice of engine. What is important though is the following:

- Easy to code (intuitive and clean API)
- price below 10000$
- good support
- multiple cameras, posibility to position/orient/zoom
- import of 3ds MAX models (with material, animations, etc.)
- fast (culling: BSP/octree/...)
- should preferably be able to code inline OpenGL to do stuff the
engine does not do.
- must run on Windows OS

I have looked for a couple of days now on the net. Most engines
describes all the cool stuff they can do, but they dont describe how
easy/hard it is to use the engine. I think this is just as important.
The candidates so far is:

- 3DState (this does only handle the company:s formats though,
otherwise nice)
- Vega/Vega prime
- PowerRender

but none of theese fulfilles our needs above. 

Any suggestions on engine to use?

Also wondering if polytrans or some other package converts nicely
between 3ds and openFlight(flt).

thanx in advance