Yes, the only differences are that mCaptcha is 100% FOSS and uses variable difficulty factor, which makes it easy to solve Proof-of-Work under normal traffic level but becomes harder as an attack is detected.
Yes, the only differences are that mCaptcha is 100% FOSS and uses variable difficulty factor, which makes it easy to solve Proof-of-Work under normal traffic level but becomes harder as an attack is detected.