The Universal Audio UAD-2 DUO is a firewire DSP engine with 2 SHARC chips. I have the Quad Custom that cost more than just the standard DUOCore. You can purchase the Quad Core, Quad Custom, or Quad Ultimate which is a lot more than all of the other models. When it comes to picking the right model I just had to figure out which unit would best suit my setup.
It comes with some very good plug ins right out of the box, but also more can be purchase at the UAD online store for affordable prices. I actually got a coupon when I received my QuadCore that allowed me to get some more plug ins at a very good price.
After I purchased the Quad Custom I was able to get free software upgrades for up to 1 year while it was still on warranty through Universal Audio. I have used these plug ins with Cubase and Logic, they work in those DAW’s just the same way they work in Pro Tools. They load up fast and don’t take too much of the CPU from my projects.
I recommend getting the “Quad” if you can afford it over the “Duo” because it will give you the best bang for your dollar and more features and a better overall sound right out of the box. But any of the Universal Audio UAD systems are good and you can always upgrade. Using the Quad has gave me way better mixes on our music than I thought I was ever going to be able to get from my home studio. It makes everything sound bigger and fills out the stereo field giving a wider feel to the vocals and instruments. Our sound is now very clean, and the fact that I can do all of this from home is perfect. Because I remember a time when you had to go to a big studio to be able to do these things and pay a lot of money by the hour to use this same type of gear.