I invested a lot of time looking for profitable traders before getting into the niche. Something around 2-3 weeks of 12+ hours a day just to find somebody whose words I can believe enough to make any conclusions.
I must say that I found profitable and believeable traders in both markets, but stock trading had much more of them. I found just 2 full-time Forex traders whose words I can believe. They don't sell any services or products, they just live from trading of their own accounts. Both of them are tired of trading.
As for the stock market, there are a lot of people sharing their results publically. I found enough to make my own conclusions.
There are also a lot of people who finally moved from future to stocks. It's just more profitable at the end.
While Forex may seem more profitable at the very beginning becauase it's so volatile, the truth is directly opposite. Forex isn't "volatile", stocks are much more volatile by their nature. Forex gives you an illusion of volatility due to insane leverage.
Taking into account average daily range of 0.1%-0.5%, you are trading purely noise. Being a software developer, I created an internal statistical analysis system to build price movement distributions. They are so close to white noise distribution you will be surprised.
As for stocks, movements have clear signals in them. Yes, there is still a lot of noise when you are day trading, but just look at higher timeframes too see the difference.
I would personally prefer stocks, I plan to convert my first product to stock trading simulator in the future. Forex is a good way to learn initial trading experience as long as you trade penny accounts, but I would stay away from it if I decide to get back to trading again.