The Digidesign D-Verb Free was quick and easy to install, as it will install itself when you install Pro Tools. It comes free with the program as part of Digidesign's free plug-ins. I had no compatibility issues running this, as it is made by Digidesign for use with Pro Tools. I don't have a manual for this and I'm not even sure that a hard copy version of it exists. D-Verb is really easy to follow and use, so you shouldn't need a manual anyway.
I am running Digidesign D-Verb Free in Pro Tools LE 7.4 on a Mac Book Pro that has a 2.2 Ghz Intel Core 2 Duo processor and 4 GB of RAM. I run Pro Tools with a Digi 002R audio interface, and I've never had any problems running this plug-in with this set up. I am able to run a few of these at once, but usually only run one and put it on a auxiliary track and send audio via buses to the aux track. This saves processing power and I always do it when running a delay or reverb. The plug-in is stable with my configuration and it always runs smoothly for me.
I've been using Digidesign D-Verb Free since I got Pro Tools LE a few years ago. While it is great to have a free reverb plug-in, this definitley isn't the best reverb plug-in I've used. It sounds good and there is a good deal of versatility to it, but it lacks the clarity and parameters to be as good as a plug-in like TL Space Reverb. You can use all types of reverbs on this, as it has presets for hall reverb, church, plate, room and ambient. It also has parameters for diffusion, decay, pre-delay, low pass filter and high freq cut. All these parameters add up to a versatile plug-in that you can get a number of different types of reverbs from. Of course, the best part of this plug-in is that it is free, and I most likely wouldn't buy it if it wasn't free. If you have Pro Tools, you have this plug-in and it is definitely worth messing around with if you do.