Absolutely love this. Love your entrepreneurial spirit. Love the fact that you didn't like something, so you're spending the time to build an alternative. It's this kind of motivation, competition, and capitalist mindset that keeps technology evolving.
From the screen shots, your interface is looking nice. Everything is clean and appears to be responsive. Your biggest challenge in the PF community is finding a way to differentiate it from Mint and Personal Capital, but you already know that. As a fellow software guy, I'm interested in seeing this continually progress.
I'd probably use a sans serif font on your website, though - but that's merely a personal preference.
I'm assuming that you're properly insured from a business standpoint, yes? Dealing with people's finances, making contributions and offering recommendations I would imagine contains a ton of potential legal ramifications if something goes wrong. I am no lawyer and don't claim to be, but this is one of the biggest concerns I'd have in building a PF app.