I must also reiterate that this system wasnt exclusively Akbar's 'creation' as generally believed, it was part of an evolutionary process of administrative reforms that started properly with Sher Shah Suri-- but Akbar was the one to truly make this system strong.
Im sorry some part is missing above, we're having some power outages out here!
Basically, instead of an effete and corrupt nobility , Akbar was able to build a class of people who were a 'nobility of merit' and who would work hard to prove their loyalty and win higher and higher honours and 'mansabs'. Akbar was also able to choose/appoint mansabdars without any consideration of religion or similar prejudices.Thus, his rule and the Mughal empire under Akbar became truly strong and dynamic.
The 'Mansabdari' system as establieshed (or re-established) by Jallaludin Muhammad Akbar, the great Mughal, had two essential points of significance
1. It allowed maximum promotion of people on the basis of merit, and of service to the Crown.
2. It dscouraged a permanent system of feudal aristocracy, since each Mansabdar's property and estates etc would revert back to the Crown on his death and his heirs would have to win their own honours. and