The Yamaha SPX990 is industry standard and found in front-of-house racks all over the world. As well as excellent sound quality and versatile programming it also has the advantages, for live sound, of patch storage on an optional removable card and pre-selection of patches. From the owner's manual:
"The Yamaha SPX990 offers 80 preset effect programs including accurate simultaneous natural reverberation and early reflections, delay and echo effects, gated effects, a versatile compressor, delay harmonic driver, multiple effects, freeze (sampling) programs which can do loop playback and others.