Question ?? TearOff Machine Feedback

Does anyone have any experience or knowledge about power tear off machines for commercial roofing. ie - panther or garlock?? must appreciated

What brand machines have you found to be worth the money. how much labor savings should i expect. what is the machines to grew size ratio? I found a panther that was built in 2007 owner claims it was used on one job aprox 45 hours, but the tires are pretty worn out. he claims to have paid 8k and is selling for 1750. THOUGHTS?