Charles,
The PE is a good toe dipping product if you are interested in a first time purchase. If you are looking for serious filtering options then I would recommend the PE V Pro, PE VI, or Quantum.
Phil,
The VI is right up there in the same league as the V and Quantum filters. I use the VI for extracting the absolute last bit of detail a component/system has to offer. The VI can be used with digital, analog, and video....I have 3 in my set up....one is used in concert with the Q LE on the primary side (Quantum at the wall and VI designed as a IEC filter)....plus I have 2 other V LE on the same circuit (mid and end)...another VI is used to filter the entire secondary (AC model) and a third is installed on the LCD TV (IEC version).
Compared to the V Pro...the VI digs deeper into the recording and pulls out the last bit of detail....after the VI sets up you as the listener will be able to tell me the guitar string manufacture and type/model...that is the kind of detail the VI delivers...those other guys can't say that, not at these prices. Compared to the Quantum, which is a more organic filter, the VI is less warm and more exacting without any hint of brightness, but it is brutally honest in its reproduction.