We'll be arriving in Ushuaia around 6th of January (leaving on the 10th). I have a men's GT Agressor 3.0, while my parter has a ladies Trek 820. Both in excellent condition. We intend to sell both bikes in Ushuaia at the end of the journey that started in Puerto Montt.
Both bikes were bought, second hand, in Santiago de Chile. They were having little use. The Trek bike even had some stickers left on from when it was taken out of the box, so I would say the previous owner did not use it at all. We cycled 2500km on them without any issues(had to change tyres and break pads, but that's expected).