I have the
Yamaha StagePAS 300 . It is a great little PA system for anything from solo work to small bands. It does not feedback at all. I use my own for DJ shows, karaoke shows and personal performances. I have also used it outdoors with combos and a small band (5 musicians). The speakers are even shaped so that they can be used as on-stage monitors, placed on the floor and angled up at the performers, if necessary. The mixer has two ouptuts so you can use it with a larger system where needed (keep the StagePAS speakers on stage as monitors and plug the other output into the house PA system or other speakers). It is also very portable. Check it out
Of course, if you already have a PA system and just need a single on-stage monitor, I can recommend the
Yamaha MSR100