The fiscal cliff will have no direct impact to renter class obviously. However the renter class pays rent to property owners based on the source of income in the following categories:
1) Jobs; 2) SSI; 3) Housing; 4) Other
#2) & #3) are not likely changed either way unless Fed Gov is bankrupt, which is not impossible if US doesn't reduce its debts eventually.
#1) is more depending on the private sectors which rely on investment capitol which will be affected by higher taxes.
If nothing is done on fiscal cliff and the taxes are restored to Clinton era, the stock market may crash again. Employers may cut work force. Working class will find even harder time to find jobs. As result, we, as property owners, will suffer more on rent loss in either lower rent rate or vacancies.
If the fiscal is totally under control or the current tax rate is not changed, the economy will recover in faster paces. The rental market will improves and housing prices will appreciate again. But Fed Gov will be in deeper debt, which might be very risky in long term.
There is no perfect solution. I believe that we will see bipartisan decision with a compromised solution.