If you don't have a UAD card of anytime, you won't be able to run Universal Audio's Dreamverb plug-in. If you do have one, of course you know that it will take care of all the power in terms of running the plug-in. They say that the card will support up to six instances of the plug-in within a single session, but I would imagine that you could do more if you so wanted. However, I've only run a few of them at a time since I use reverb plug-ins on an aux channel to save processing power anyway.
While I don't know a UAD card for my home studio system, I have run sessions on a system that does and that runs Universal Audio Dreamverb as well as a number of other UAD based plug-ins. I have to say that in general, I think the UAD cards are great as they really help to save processing power and is perfect for those running anything less than a Pro Tools HD system. In terms of sound, Dreamverb seems to have endless amounts of varying tones. All of the effects are high quality and just about as realistic sounding as you can get from a plug-in. If you have any interest in this plug-in or the UAD card and pack, I'd definitely encourage you to explore this curiosity as I believe you'll be quite pleased with what you see.