I am a guitar player. I wanted keys for my home studio with limited space. I am not a piano player, so my review will not focus on piano-centric features.
Keys: stiff! I have a direct comparison with hammer action graded piano and although Roland doesn't feel like that at all, the pure stiffness translates into higher effort needed to play it vs typical synth action keyboards.
Build quality: I'd say plastic fantastic but good quality plastic
Speakers: I use them at low volumes only. They're OK for practising. HOWEVER: some patches, including main piano sound sound crackling/distorted! It is not rattling. It is electrical issue. It was proven and verified by other people by opening the keyboard, disconnecting the small internal speakers and using external ones instead. The crackling persisted. Headphone out: no issues. Quarter inch outs: I have not tested. I hope they can fix it with firmware update.
Synth and samples quality: no issues here. Better than most competitors and expandability is a huge plus.
Arrangers features: very good styles, modern, not typical cruize ship/elevator/waiting hall junk. Big cons: you cannot mute individual instruments. Only drums, bass and "all the rest". You cannot swap instruments for different ones either.
Overall I am happy. It is compact, sounds more than OK, I can finally pretend I know how to play piano :)