As a trader, where is it "easiest" to become a millionaire?
At Forex trading or by trading Stocks at the market?

*What is the big difference between them both?

Answer
Forex is a "zero-sum" proposition...the only way for one Forex trader to make a profit is for another Forex trader to make a loss...

Stock trading allows for any (or even all) holders of a particular stock to make a profit, so long as the underlying company remains in business.

It is easy to become a millionaire buying (and holding) quality stocks...

Forex vs Stocks??????

I would like to compare both based on ROI, efforts involved, risk factor and learning curve.

Those who have done both, please share your experience and let us know which is worth putting efforts as a newbie on both.

Answer
Forex:
Better ROI than Stocks
Efforts: More than Stocks
Risk: Equal if managed smartly otherwise riskier
Learning Curve: Almost same