The RH3 key action feels amazing and provides an excellent range while playing.
The on-board sounds, while I don't think that they reach the studio-level quality of some other Korg keyboard, are definitely good enough for stage or amateur music production.
The instrument itself feels solid, and it's not that heavy (15/20 kg).
The features it offers are pretty basic, like layering or the metronome, and it lacks some of the stables of competing models, like splitting and internal speaker.
This last one is especially a bummer for me: sometimes I want to play for other people and it is really practical to just press the ON button without having to fire up an amplification system...
But I wouldn't really consider it a con, since I think that this model aim is to be integrated in a studio environment as a controller with internal sounds.
As for connectivity it offers two stereo/mono line OUT, an headphone port and the standard MIDI IN/OUT, which can be converted to USB with a cheap interface in order to communicate with almost any DAW.
In my opinion a great piano for just about everyone, especially people interested in music production.