Selling credit spreads is safer:
1) Effectively, it's a 'naked put' with 'protection'
2) If the market moves against you 2% or 50% your maximum loss is locked in
3) You can manage your portfolio and margin based on your maximum loss which can easily be known.
Note:
If you have a bull put credit spread, you no longer need to worry about a stop-loss order. In fact, a stop-loss order may work AGAINST you. (Forcing you to sell when you get a 20% loss, rather than waiting longer in case the market rebounds). If the maximum loss (the spread between the two strikes) is too much for you, then you need to narrow the spread, decrease the order size, or consider an alternative strategy.