One of the great feature I like with TradingView is the ability to compare different ticker via arithmetic addition/division/subtraction. From here, I'm comparing between UNG and USO. Since both are directly related to energy, tough choice huh? Charting it out helps a lot and we can see a clear breakout trend between the ratios!
Clearly Natural Gas (UNG) might possibility provide the best return for your money on energy as compared to Oil (USO) over the long run.
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** Note: USO have been severely under performing since 2008 after the recovery of oil price due to the price difference between each month's oil futures contract. It will not be a clear reflection of the actual market.
This is only if you're considering between USO or UNG. Try it out by charting other ETF/ETNs/stocks by yourself!