[Elan]

I'm curious, has anyone actually noticed a difference between when you quench a reaction slowly versus when you quench it rapidly (i.e. drop-wise versus stream)? I've always been taught that faster is better, but I'd like to know what you all have learned from your experiences.

[Zensation]

As long as doing it fast doesn't produce excessive heat and cause valuable product to splash into the condenser or other connected pieces, then I say go for it. If it does produce excessive heat and your substrate can handle it then go for it. This is of course a general guide line and would vary depending on reaction conditions.

[TheUnassuming]

It really depends on the reaction being quenched and how you are doing it. 
If there is going to be gas production in the quench then slowly is a good call.  Also as already stated if there is going to be heat produced by quenching (like most acid/base quenches) you should go slowly as well unless you know your compound is rock solid stable and the solvent won't boil out. 
Generally start slowly, especially with a new reaction, until you know how its going to react.  Better to possibly loose some yield due to that than because it erupted out of the flask.