M.C. Welcome to the forum! You'll like it here.
There has been a lot of discussion on the merits of the 2100 and 2000, which are virtually the same. As I recall, there was even some comparison between it and the Technics KN2600. You might try the search engine to retrieve this information.
I think you'll end up choosing the Yamaha.
Ketron does make an excellent arranger module, comparable to the latest keyboards. I'm sure someone will chime in with a description of it, although traffic is usually quite slow on Sunday.
DonM