Hi,
I had a pair of Penta III's for 10 years. I was very very satisfied with the sound (and looks). To me the sound is smooth, relaxed and very 80's style with good bass and not too crisp sharp high-end.
After getting a BV7 with BL 7.4 and BL3's as rear I discovered that the Penta's sound didn't fit the new range of speakers with ALT. These new speakers have a very detailed and crips sharp high end and the Penta's don't. This is nothing bad for the Pentas but just different type of sound. I had to shift the Pantas to BL9's in order to get a set-up with equal type of sound and details, as a 5.1 movie / sound track was very strange to listen too with the different type of sound from the speakeres.
Too me the Penta's are very good but not to be used in a set-up with other ALT based speakers.
Ken