Are you married? Have any family commitments?

If no, I would say go for it as you would not be too adversely affected by the 20% paycut (think of it as subsidising your PhD course) while you can/should be able to handle the workload with no fear of a kid popping up in that 4 years.

At the end of the day, its well worth the effort as you gained some very marketable skills/qualification to propel you along your career path.

The 2 year bond is also very minimum, atleast its not 4~5 yrs some company is asking for.