The topic is vague indeed. The truth is, the condition or state of any plane is more a reflection on the owner of the plane rather than anything to do with the craft itself. Neither the 727 nor the TriStar can ever be considered a bad type - they were both revolutionary indeed. Just look at how many 727s sold (1831) compared to its contemporaries which flopped - BAe Trident (? how many built), Dassault Mercure (10) - both of which were in its class. In addition to that, well over 1000 727s still fly while Trident and Mercure lie in the graveyard. It is true that some carriers neglect their older planes and let them run-down until new ones arrive but again that is the fault of the airline, not the plane!
As for TriStars, BWIA has kept its 4 in excellent condition and 2 now sport the steelband logo which can be seen in photos on this site.