Oil price is hitting the bottom much quicker than real estate market. That's my call.
However, owning USO for long term may not be a good idea, given the so many factors that you or your friend can manipulate the crude oil price for whatever reason. If you really love oil, DIG yourself a hole and bury some greenish paper in there. Don't forget to say "Alibaba" after that. You will be humbly rewarded.
_:)