I think if you play solo (or duo) mostly then the Bose System is hard to be because it sounds great in smaller to medium settings and you can plus a mixer into it to plug more mics or instruments.
I'll have to second the Behringer powered mixer (800 watts 2X 400) I have been using it for a while now and have no complaints. Plus it is so light and about half the price of a Mackie 808M (what i WAS going to get).
It's just plug and play and thats the way I like it!