PSP's Lexicon 42 is a plug-in that is modeled after a Lexicon hardware delay. The process of installation wasn't difficult. Just follow the step by step instructions that come up when you launch the installer and you should be good to go. It only took a few minutes for the whole process to be completed. The interface of the PSP Lexicon 42 is pretty simple, and it looks like it is a single space rack mountable piece of gear, just like a real piece of Lexicon gear. The interface is split into a few different sections, including those for input, delay, and VCO (voltage controlled oscillator) sweep. Each section has a good amount of parameters to work with, and there are some parameters for filtering as well. I haven't seen a manual for the PSP Lexicon 42, so I can't say anything about it.
I'm no longer running the PSP Lexicon 42 plug-in, but when I did run it I had it going in Cubase SX. A number of years ago I switched over to Pro Tools and never got an RTAS version of the plug-in to use with it. The computer that I was running this plug-in on was a Hewlett Packard Pavilion dv8000 lap top with a 3.0 Ghz processor and 2 GB of RAM. I ran the plug-in in Cubase SX and a MOTU 896 HD audio interface. I don't remember having any problems in terms of performance within this configuration.
The PSP Lexicon 42 is overall a really cool and useful plug-in. It's definitely one of the plug-ins that I wish that I still had from before I switched from Cubase to Pro Tools. I believe that it comes in a variety of formats including VST and RTAS, but I just haven't had a chance or a need really to get a new one in RTAS format. There are a ton of different interesting sounds that are possible with this plug-in, ranging from traditional sounding delays to more non-traditional sounds. I love the way the interface looks as it makes it easy to use and gives you the feel of a piece of outboard gear. If you're looking for an in depth delay plug-in that goes beyond your average delay, the PSP Lexicon 42 is definitely worth checking out.