The A100S is the successor to the A100. The biggest improvement is the new keyboard.
It feels more robust like a professional organ/synth/keyboard.

The build quality of the buttons, knobs, tone wheel, and keys is amazing. Furthermore, the A100S is equipped with an impressive 700 Voices and 280 Styles. You can even record and save your performance to Drive and share it with your friends. In addition, you can connect it to a PC or laptop and access different music programs. You can also save the settings in the "record" buttons. With the push of a button you will open the voice, style, metronome speed and much more. With a professionally tuned stereo system, the A100S produces impressive sound. From beautiful, dynamic sound to high-quality feel and touch, the A100S provides just about everything an aspiring keyboard player could ask for.

Specs:

Keys: 61 keys with touch feedback Display: LCD Polyphony: 128 Voices: 700 Accompaniment Styles: 280 Registration Memory: 48 Songs: 120 Demo: 5 Recording: 1 track, 5 songs Connections: DC power, headphone/line out (1/4" jack), multifunction pedal (1/4" jack), USB MIDI: USB-MIDI Power supply: DC 12 Volts/1000mA or 6 AA batteries Speakers: 2 x 10 Watt, 4 Ohm Dimensions: 970 x 370 x 142 mm Weight: 6 kg without batteries Included accessories: Power supply (MAD 12/1000), Music rest, manual