Rolands are known for so-so factory kits, with a heavy emphasis
on unusual sounds. And for having a decent set of
sounds available if you are willing to edit kits yourself.
The demand for better kits actually spawned a company
that just makes "kits" for Roland modules. They are quite popular
in the Roland community. Their prices are pretty reasonable too.
I have one of their kit packs for my TD-9. Really helps show off what it can do.
- the forum there is good too, a bit Roland centric,
but good for most e-drums.