The major similarity between these two revolutions is that they were both waged against an unpopular autocracy.  The Russian Revolution was meant to overthrow the monarchy while the Mexican Revolution was intended to overthrow the autocratic rule of Porfirio Diaz.  It is also worth noting that both revolutions were followed by civil wars between various factions that wanted to take power.

The major difference is that the Mexican Revolution was largely a revolution in favor of democracy.  The Mexican Revolution did not lead to any sort of a communist government.  The PRI was not perfectly democratic, but neither was it totalitarian in the way that the Soviet government became.  

These two revolutions were fought to overthrow unpopular autocratic governments.  But they had very different results in terms of the governments that they put in place to replace the autocracies.