Oil Free compressors are less expensive, lighter in weight, produce as much air flow (CFM) & pressure (psi) as many oil lubricated models. However, they are loud & much less durable than an oil lubed cast iron pump. But they can be a good choice for the very occasional DIY or homeowner.
Cast iron, oil lubricated air compressors are more expensive & heavier but are much quieter & last several times longer. So if you are a commercial or serious DIY user, then an oil lubricated, cast iron compressor is the only choice. Spending more for an oil lubed model will more than payback in the long run. Buying two “cheaper” compressors instead of one quality model can actually cost more in both dollars & frustration.