Hey Matt,
That's a great price for maple, especially out West. It goes for $8 a board ft around ABQ. Who's your supplier?
To answer your question, I used to use a lot of maple when I lived back East and could get it cheaper. I used both hard and soft. There is nothing "soft" about soft maple, only comparatively softer than hard. I would definitely save the extra bucks.
One thing to look out for in maple, especially soft maple, is how figured it is. The figure is beautiful, but its hard to match figured pieces and the figure makes the wood harder to work - good chance of tearout. So figured is good stuff, but it is a lot more work than straight grained.
Sorry this got so long, bottom line answer is that either will work fine!