Hi Roman,
Yes - this seems more on the right track for me, as there are measurable differences for the pages based on the following metrics:
Links 2
Reffering Domians 2
Keywords 20
I will use the Moz tools to check these out. By way of further explanation as to why we are so stumped by this problem, here are two summaries of our analytics performance for the two pages over the same period - the differences seem unbelievable:
www.machinetoolsonline.co.za/buy-used-machine-tools
284 sessions, 74.91% new sessions, Organic referrals 246
www.machinetoolsonline.co.za/buy-new-machine-tools
5 sessions, 80% new sessions, Organic referrals 4
I will update the thread. Any other suggestions are welcome!