Zenith, Curtis Mathes and GE Consoles

Just picked up some vintage console stereos and I'm interested in keeping one and selling the others but I'm trying to get some info (vintage, quality, etc.) of them before deciding the details. One is a General Electric model RC 7839 A with AM/FM radio & turntable, one is a Curtis Mathes model 44-6 also with AM/FM radio & turntable and the last one is a Zenith Allegro with AM/FM radio, turntable, 8 track and cassete decks. Not exactly sure of the model number (I forgot to write it down and I'm at work right now) but looking online it looks like a late 70's/early 80's unit. My teenage son and I are new to this so any guidance will be very much appreciated.

Thanks!