Casio has been producing great pianos for many years, and their Privia line is one of the most renowned and sought after pianos.
The Casio Privia PX 350 is an example of this. It’s a great stage piano on the lower end of the pricing spectrum (stage pianos can go for up to four and five thousand dollars in price).
The PX 350 has 88 keys with real feeling ebony and ivory tops. It comes with 128-note polyphony, an amazing 250 tones, and a massive 17 track, 5 song recording system.
It is supported by Casio’s Tri-Sensor Scaled Hammer Action II system and their AiR sound source, which might just be the best bang for your buck for the $700 price range.
A comparable piano to this would be the Kawai ES100. Kawai digital pianos are pretty well known, although I feel they are more recognized for their real acoustic and grand pianos.
Still, the ES100 is a great machine in the same price range, also having 88 keys and a comparable hammer action system (Advanced Hammer Action IV-F). However the ES100 is more of a standard stage piano in that it does not have nearly as many tones (19), but it does have a bit more polyphony (192 notes). It uses the Harmonic Imaging (HI) ,88-Key Piano Sampling sound source. More at http://bestrateddigitalpiano.com/how-to-find-and-select-the-best-digital-stage-piano/.
At the very high-end spectrum of stage pianos, there are some really amazing options, even though you should be prepared to spend a pretty penny.
There is the Yamaha CP4, which some claim is the best digital stage piano made by Yamaha. This machine features an astounding 45 grand piano sounds, 47 vintage electric pianos, and 341 other voices.
That collection is almost unheard of.
It has a beautiful hammer wooden key action with synthetic ivory tops, and weighs in at an unbelievably lightweight 38.5 pounds.
However, let’s not count out the Kurzweil Artis, which features a 9’ German grand piano sound to go with 255 other stage sounds. It has 128 notes polyphony, its own hammer weighted key action, an impressive FX engine to help you modify the sound, and sliders, switches and wheels to make up its programmable controller system. More at http://bestrateddigitalpiano.com.
The Roland RD-800 is another piano that falls into this discussion as well, as it comes with 88 keys, Roland’s best Progressive Hammer Action 4 system, the SuperNATURAL piano sound engine, and a whopping 1,113 tones!
This piano also comes with 200 live sets to choose from, along with sound FX modulation and other features. These pianos can cost anywhere between $2000-$2500.