The Digidesign DigiRack Multi-Tap Delay is a plug-in that comes free with all versions of Pro Tools I believe. The process of installation is virtually nonexistent here as you don't need to take any further action beyond installing Pro Tools. It takes care of installing all of it's free plug-ins when you install Pro Tool initially. You're never going to have compatibility issues with the DigiRack Multi-Tap Delay since it is designed by and made only for Pro Tools. The interface of the plug-in is very simple all around. Essentially it is broken up into four different sections, or 'taps.' Each has sliders to control the level of gain, feedback, pan, and delay in terms of milliseconds. There are then two mix sliders on the bottom to control two of the delays each. You can use the plug-in either on individual tracks or as one time processing in the audio suite. A manual isn't needed for this plug-in.
Right now I'm running the Digidesign DigiRack Multi-Tap Delay plug-in in Pro Tools LE 8. I don't know how far back this plug-in goes, but I believe that most versions of Pro Tools have this. The system that I'm running this on includes a Mac Book Pro lap top 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. I always run this plug-in and other delay and reverb plug-ins on auxiliary channels and bus the individual tracks to it in order to save processing power. While this isn't really necessary with this plug-in since it doesn't take up much processing power, it's still a good habit to get into.
The Digidesign DigiRack Multi-Tap Delay isn't my favorite of the free delays available in Pro Tools. I can't say too many bad things about it since I didn't pay for it outside of buying Pro Tools, however, the sound of this one just comes off as inauthentic to me. While there is a good amount that can be done with it in terms of varying delay effects, most of the sounds aren't suitable for what I want to do with it. It's really not a big deal for me as I have other delay plug-ins in addition to the other free delay plug-ins in Pro Tools 8 like the AIR plug-ins. Either way, if you've got Pro Tools I'd encourage you to check this one out for yourself anyway.