I think pipeline MLP qualify as having being good source of income and are less risky than a trip to Vegas. It is highly likely that their volatility will continue to be be very high, due to highly volatile energy prices, the credit crisis dramatically increasing expansion costs, and the dumping of MLPs by hedge funds facing liquidity crisis.
So I would be shocked if we don't see the stock prices raise and fall by 20-50% each month for the foreseeable future. Most of the MLP I own saw ~10% changes on a daily basis last week.
On the other hand I would expect to see distributions from them to remain flat to increasing modestly over the next year. For the most part their income is primarily related to volume of natural gas/oil and not the price. So if you buy them and resolve to not to look at the price for a year I think they are a good investment. FWIW (what you pay for it), I am lightening up on financials and increase MLPs in my search for higher income portfolio. If you are looking at more than 5 figure investment in MLP, the M* dividend investors newsletter covers them extensively, signing up the newsletter (30 day free trial) is money well spent.