Markus,
Much of your success in live situations depends upon how much time you dedicated to learning the operating system of YOUR keyboard. For me, I like the Yamaha PSR and Tyros operating systems, Fran Carango prefers his Roland G-1000, while others will swear by their Korg, Casio, and a host of other keyboards they feel comfortable with while performing.
The secret to success during any live performance, particularly if you have a dancefloor filled to capacity, is the ability to read the audience, make decissions based upon your experiences with that type of audience, then provide them with seamless entertainment. This means dead time between songs cannot exceed more than a few seconds, and you play the music THEY enjoy and react positively to. If you can do this, you'll have more work in the OMB entertainment industry than you can handle. If you cannot, the best keyboard in the world will not earn you a living.
Good luck on your decission,
Gary
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Travlin' Easy