It will definitely work in a PA system, assuming you're not entertaining 3,000 people with 18 musicians. You would have to spend quite a bit more to improve on it. It has balanced +4dB outs that will get full value from PA power amps. It also has group and aux sends that allow you to make a monitor mix. The two things you would need to add would be a reverb box and a multi band EQ. It also comes with a highly amusing booklet, thrown in for free, which Yamaha have entitled a manual.
There are a good number of happy MG users on this forum - if you need specific input then ask away.
(edited to note my post crossed with malling)