Although I really put hard work into balancing levels for each rackspace or song, there are still some issues with some very peaky FX or percussive sounds. If they would set the max level I would need to provide much headroom on all other sounds.
Therefore, I have a low-latency and quite transparent sounding compressor/limiter in the global rackspace as the final stage before output. Same setting for all rackspaces or songs. That nails down the peaks without sacrificing transparency. Indeed, it gives FX sounds and percussions even more power and punch to my sounds, and relaxes the stress level of the FOH mixer when looking on my levels on his console.
My recommendation is the Tokyo Dawn Labs TDR Limiter. See some discussions here: