I'm tossing a coin between PS Engineering PM 1000 II or the Sigtronics
SIC-4

I've not owned the individual models that you mention, but I've owned and
used intercoms made by both companies.

PS Engineering's intercoms are head & shoulders above Sigtronics, IMHO. Of
course, I think you'll pay significantly more for them, too -- at least
their high-end stuff.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"