1) Far lighter
2) No built-in speakers
3) Because there are other sounds drawn from the Motif series, there's probably going to be more quality and breadth in its "extra sounds"
Basically, they're not that comparable. The ES7 is more suited to a "mixed" use, as it has a home stand and pedal unit available to match, whereas the CP4 is aimed at stage use.
This is largely correct, however I believe the ES7 is still an excellent choice for piano-oriented players that require a portable instrument - regardless of the fact that it features built-in speakers.
It's a little heavier than the CP4, certainly, but only by 3kg or so.
Cheers,
James
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