One of the big factors of us buying our Aframe was that it fits (barely) in our garage. I couldn't find a used twin bed version in our area so we bought a new one.
A gently used one might be better in that the kinks should have been worked out by the original purchaser. These things are not high quality - even though they cost a lot for what they are. You will hear lots of horror stories. The problems receive much more attention than the units without issues.
Just know that whatever you get will need more maintenance that you thought. There are a lot of cheap parts that receive a lot of use & abuse. I'm not trying to be negative but realistic.
We absolutely love our aframe. Despite the problems we've had would do it all over again.