I also need them to be switched on and off at relatively high frequency, and the should not burn after little use
Switching at high speed is no problem and will not contribute to excessive strain on the LEDs or the drivers.
? an array of 20-30 "super bright led" , or just some "high power" (1W/Led)
The collection of small LEDs is easer to cope with as the power dissipation is distributed and you can use resistors as current limiting devices. With a power LED you have to have constant current drivers which are more expensive. Also you have a lot more heat concentrated in one place that has to be got rid of using heat sinks.