I've heard great things about the Kawai ES110 - great piano sound + action. Only two sensors, so not ideal for fast repeated notes. I also read that you can use it with a $100 lithium battery power supply and play 8 hours without plugging in.

This would be my top pick among the light keyboards.

The Casio action is noisy, and gets noisier with time, but I have to give them credit, they extended the warranty 1 year when you register the keyboard at their website. And when I brought in the keyboard to repair the noisy keys - and it wasn't outrageously noisy and the keyboard played fine otherwise - Casio covered a replacement key bed for free.

I have a feeling that Casio might be replacing their Privia line this year. Hopefully, they will make some significant upgrades to their lineup.