The first question becomes, How handy are you with maintenance and repairs? Everything from plumbing to minor carpentry and electrical.
If you feel comfortable in those areas, then I would definitely suggest used for starting out. Look for water intrusion, possible delamination as well as visable signs in cabinets and the "feel" of the floor. The condition of the flooring in the main walkway and at the entrance give an idea of the amount of use it recieved. Check the age of the tires as well as tread, over 4 years old, replace.
There are a lot of video's on you tube that outline these things, watch a few and it will come together.
If you arent comfortable with maintenance and repair, you may want to reconsider, because things do break, and as Mr Murphy said what can go wrong, will go wrong, at the worst possible time.
But for those days it doesnt,,,,,, they make the rest worth it.