Plug Power (PLUG 6.52%) and ExxonMobil (XOM 0.18%) are in different stages in their life cycle. Regardless, comparing these two energy companies can be informative for the longer-term investor. Fool.com contributor and Finance professor Parkev Tatevosian picks his best stock to buy of the two.

*Stock prices used were the afternoon prices of May 1, 2023. The video was published on May 3, 2023.