The 3070 is no longer manufactured....but it is still a very strong high definition class plasma system. There is a torch upgrade available from Hypertherm that allows you to use the new HPR130/260 torch on that machine....better cut quality and longer consumable life are the result.
That system is a high frequency start torch.....so be sure you follow all of the best practices available for hardening your cnc control and electronics ffrom this source of electrical noise.
The system has good consumable life as is...assuming it is operated as designed (follow all the procedures in the Hypertherm manual in regards to gas pressures and flows, cut speeds, arc voltage and pierce height). With the HPR torch it will perform even better.
If you are only cutting carbon steel....you will need oxygen and nitrogen for this system when using the original torch....if you are using the new HPR torch.....you will use oxygen as the plasma gas and clean/dry compressed air as the shield gas.
You can download a manual from the www.hypertherm.com website if you need one....be sure you specify whether you have an "auto gas" or "manual gas" system......the auto gas has all digital gas flow controls....while the manual gas version has flowmeters and gauges.