With MPLX agreeing to buy MarkWest Energy for nearly $16 billion, we decided to see if there are any other stocks in the oil and gas storage and transportation sub-sector worth investing in. The sector's revenue is based on dollars per volume stored or transported. In the current environment of ample supplies, and rising demand for energy due to a growing economy, firms and industries that use energy increase their stockpiles or inventories. This is beneficial to the energy storage and transportation sub-industry. Here are some of the best stocks in that sub-sector TheStreet Quant Ratings says you should consider looking at. Number 4 is EQT Midstream Partners. With an 'A-' rating, the company's strengths can be seen in its revenue growth and increase in net income. 3rd is, Buckeye Partners. This rating is also an 'A-.' Buckeye thrives in its compelling growth in net income and good cash flow from operations. 2nd is Spectra Energy. With an 'A-' rating the company flourishes in its revenue growth and expanding profit margins. Number 1 is Magellan Midstream Partners. This too has an 'A-' rating. The company's strengths can be seen in its notable return on equity and expanding profit margins. TheStreet Ratings are algorithmic stock picks based on 32 major data points. S&P 500 stocks rated 'buy' yielded a 16-and-a-half-percent return in 2014, beating the S&P 500 Total Return Index by more than 300 basis points. For the full reports on these stocks, you can check out TheStreet.com/QuantRatings.