Low pricing (good yield) on OHI is a reflection of concern related to medical properties. The major concern is that OHI is subject to Medicare reimbursement rates leading to political risk. This is a well run REIT with a committed dividend policy. Other similar companies have the same relative pricing Think CCP, SNH, MPW.
AROC though a corp is effectively the General Partner for APLP. In addition to the APLP units it owns it has Incentive Distribution Rights. If and when APLP earnings support bigger dividends, AROC's cash flows will increase faster.