Hi --
I would describe Remie's speaker as "Just OK for the price." I don't have a PSR E-series for comparison.
It's definitely better than Reface, which is not saying much. Probably, even a low end E-series is better just on specs alone:
E263 Remie
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Stereo Mono
2.5 x 2.5 watts 1.4 watts
12cm x 2 8cm x 1
-- pj