The thing about built-in harmonizers on arrangers, none of the arranger companies have a well regarded standalone harmonizer pedal. If any at all. I figure, if they haven’t got a decent standalone version, how good could the built-in one be?
The best selling harmonizers are by TC-Helicon (I have a Perform VK) and Boss. None of whom make arrangers. Korg used to license some TC technology (not sure if it made it to the lower end models), but dropped it for the PA5x.
The only thing built-in harmonizers got you is better integration into the OS, but they simply didn’t match up to the standalone harmonizers (IMHO).
An arranger is just a tool. What matters is what you build with it..!