Re: 954 steering damper
How you ride your bike will make a big difference to the probability of having/severity of a slapper, i.e. keeping a light grip on the bars, using your knees to grip the tank and keeping your lower legs loose to absorb shocks. Having your suspension set up correctly will also help a lot.
Having said that, I'd still rather have a damper than not - I've found it really reduces front end flightiness, and I feel a lot happier laying down the power knowing it's there- I had a few minor shakes upfront before I got mine, and I was always a little wary, especially as I ride a lot of twisty bumpy roads.
I reckon it's worth it for the peace of mind alone.