You are right to be skeptical. Forex, like many other "opportunities", is full of charlatans and snake oil salesmen. I think the others that have replied are fairly accurate in their assessment of the common complaints you see on "broker review forums." It's also helpful to know who supports the forum and if the comments are censored to favor certain dealers or services.
Here are a couple interesting pieces posted by two different dealers. They are obviously biased toward their own business models, but there is some useful information on choosing a dealer.
FX Solutions Company Profile
and here:
Questions for Forex Brokers about Spreads
IMHO, for forex trading: Do not deposit more than you can easily afford lose. Deposit only
risk capital. That means money that could disappear from your wallet and you wouldn't miss it. Regularly withdraw profits and place them in a safe account outside your dealer account. If you do trade forex, it should represent only a small percentage of your overall investment and trading portfolio. Best of luck with your trading