I guess I should further qualify my statement.
As I said never buy rental fleet skis. These are the skis which are sold as a general rental model and are only available to shops to buy as an entire fleet. Atomic R series, Salomon R series, Head R series, etc. The R actually stands for rental. They are cheap crappy non-retail skis. Never ever buy these. They are terrible skis to begin with, cheap construction, cheap materials, etc. and are not worth whatever price a shop charges for them.
Demos on the other hand as I said in the post are fine. Demoes (at least at every shop I have worked at ever) are retail skis that are readily available to try out before buying a new pair. These skis are always retail skis that anyone can buy at a shop. And as I said those skis are fine. Usually in good enough shape and sometimes worth the price.
So once again.
Rental Fleet Skis = Shittiest skis out there.
Demo Skis = Fine skis as long as they are maintained correctly by the shop.