We love our Coleman. It has the ABS roof and hand-crank cable lift system. Looked at several and while we liked the Coleman, it was the condition that really put it over the others.
Go examine each carefully, set it up and take it down yourself at least once before you buy it because the current owner wont be there to help later. Look for damage or rot or sagging. Shake things and make sure it'll stand up to real use. Pay particular attention to the roof and attachment points and lift system, get under it and over it and be certain it won't crash down on you in your sleep even in a storm. Check the seams of the enclosure and where it attaches to the roof and box, every inch (I found a 6" section pulled apart at the roof in the middle of the wall later.) Check the door action, appliances, outlets and lights, propane system ...everything. Seemingly small repairs can be expensive so don't assume it is a cheap fix.
Time and exposure is very unkind to popups and it isn't always obvious.
Best of luck!