I subscribe to The Motley Fool newsletter but haven't actually bought any of the stocks they recommend … yet.
My friend used to work for Motley Fool. His answer is, it's better than most mutual funds, but they aren't rocket scientists.
Motley Fool caters to the buy-and-hold crowd, people who buy a stock and then hold it for at least a year, and usually several. You can expect 10-20% a year, long-term, from their recommendations, which is better than most mutual funds, but on the other hand, anything can happen in the stock market.
The question you have to ask yourself is, if you're going to blindly buy whatever stock they recommend, are you really learning anything? And if you don't blindly buy everything, then how will you decide which to buy?
If you're willing to put a lot of time into learning investing, the rewards can be far more substantial than most finance professors and mutual fund managers lead you to believe. I recommend How to Make Money in Stocks by William O'Neill or www.investors.com (Investor's Business Daily).
If you want a great stock-picking website run by an actual wealthy trader, try www.chartpattern.com. I've used it profitably for years. Dan Zanger (read up on him; his track record is truly impressive) does not tell you to buy or sell – he reads the market, and then recommends buy and sell points. It's much faster-paced than buy-and-hold investing, and not for everyone, but it does work.