All of the above answers are good and to the point. The only thing I might add, as a live performer, is select a keyboard that allows you to do things quickly and efficiently on the fly. One that allows you to perform a multitude of tasks while performing a song in front of a live audience, and do this in a manner that does not detract from your performance.

There are lots of great arranger keyboards available today, most of which would be an excellent choice for live performances. Despite the petty bickering you read hear about sound quality, there is not a hill of beans difference between the TOTL boards, especially if you take the time to tune them to your sound system. It's what you do with the keyboard during the performance that counts most.

Good luck on your decision,

Gary