Any experience with the ULTRACURVE PRO DEQ2496

Yes, much experience with mine. They have had some issues with reliability, but my second unit has worked perfectly (first one had some issues with not holding presets). Mine is 100% transparent, 100% quiet, and has zero sound signature when in line with my sources. I use mine for balance issues due to hearing loss, and honestly it has saved me from selling all my gear and saying to hell with audio. Buy a new one, and you'll be happy.

I've provided and set up a number of DEQ2496s for professional venues, that wanted to go the cheapest route. I've got one, for(remotely) testing my room & system, after running my TacT RCS 2.2 curve, via the 2496's spectrum analyzer function. I'd never consider actually having one IN my own system. There are companies that will upgrade them, to lesson the distortion, veiling and digitized sound. ie: (http://www.behringermods.com/deq2496.html) If you are at all competent, regarding electronic upgrades and DIY projects, here's another option: (http://www.awdiy.com/)

It depends. I have one, but I only use it for certain things. It all depends on the room, the components and what you are trying to do.