has anyone yet used one of those professional QUADRO FX video cards for their Bryce work, and if so, are they significantly better in openGL rendering compared to standard gaming video cards?

I believe (but not completely sure) high-end video cards like the quadro use a different opengl language than the mainstream cards do. Over at DAZ I have read one angry members brief account of how their opengl was "bad" with their quadro fx.

They used much more descriptive words than "bad".

Still all this is no better than speculation, lol.

OpenGL is OpenGL, although like most things the langauge has evolved through several versions, I use a quadro at work (all be it a slightly older model 4 version), with 3ds Max it's fantastic, you get things like live fog in the working viewport, but to be honest Bryce's implementation of opengl is still a bit behind, I don't get error messages, it just looks terrible and sometimes objects don't line up quite right between openGL and render which is very frustrating

Yep, frankly DAZ Studio and Poser both have more updated use of OpenGL then Bryce does. Bryces OpenGL preview seems very basic compared to other apps. I still tend to stick to the wireframe in Bryce.

Hardware OpenGL works well in Cinema4D (I am using an Nvidia FX5900 XT not a Quadro though but have heard many happy with it on CGTalk's cinema forum).

Where you see a difference is these cards are much faster at pushing vertices and geometry to the GPU and GPU memory then normal cards are as well as "supposedly" more stable drivers. Of course they charge a premium for these products that basically use most of the same hardware as the high end consumer level cards.

I dont know how it works in bryce, but I've seen the faster quadro fx cards be up to twice as fast in 3dsmax as the fastest Gforce cards around. So... if DAZ did their job well on the openGL support it should be a nice fast card? Then again, I highly doubt the price-tag is worth the trouble if you're using bryce as bryce's openGL views aren't the most brilliantly usefull openGL implementation. Plus the card wont boost ur rendertimes one bit. If ur swimming in money then hey, why not give it a shot? but else I think there would be better ways to blow $1000+ on hardware.