Tax on 403B withdrawal vs Soc Sec benefits

Hello, 

I am 64, thinking about retiring from work next year, need to decide if I want to sign up to receive Soc Security benefits or instead withdraw about the same amount from 403b investment for living expense.  I am trying to weigh the pro and con of each alternative.  The pro of delaying SS benefit (until I turn 70) is the guarantee of increasing monthly benefit of about 8% annually, vs. the risk of fluctuating stock market yields with the 403b.  The other factor to consider is to know which income may be more tax favorable.  I am in the 22% tax bracket, as my spouse will continue working and have an income from work.  Can you speak to which income source would be more favorable from a tax perspective?  Also, are the other factors to consider?  Thanks!