Yamaha appears in more of our families than any other manufacturer: an ARIUS
console piano, two PSR keyboards, two beginner guitars and a pair of HS
monitors. That is not a preference — it is what the catalogue looks like when
you sort each family by what is actually sold and supported.
What we found writing the reviews
The specifications are published where they matter. The PSR-E383 states
48-note polyphony, which almost nothing else in its price bracket does. The HS4
states 60 Hz – 22 kHz and 102 dB SPL. The ARIUS names its action as Graded
Hammer Standard. Where a figure decides a purchase, Yamaha tends to print it.
The entry guitars are the most consistent instruments here. The F310 and
the C40II have been in production long enough that their build quality is a
known quantity, which matters more at this price than any single specification.
Four of the six are absent from the US store, including both guitars and
the ARIUS. That is a distribution decision rather than a defect, and it is why
our American readers are sent to a local search on those pages rather than to
a reference that does not exist there.
One caution on price. The Spanish price for the ARIUS stood well above the
German one at the time of writing, and the UK price for the PSR-F52 at roughly
double the German. Same reference, very different money — check your own store.