> Are you talking about the lambda value (the damping factor)? If so I'd argue
> it's more like the same value for most gradient descent -- more controls the
> speed of learning than the outcome (although that isn't necessarily true with
> local minima).

I am talking both about the damping factor, and the preference offset. In
my experience these are not at all universal on all datasets. One example
is the clustering comparison example
http://scikit-learn.org/stable/auto_examples/cluster/plot_cluster_comparison.html

I had to tweak these two parameters pretty badly to get a somewhat
satisfactory anwser on all datasets, and as you can see, the parameters
don't really work well on the different datasets.