That PMI is a huge downside, so I'd say work on your options for the best way to put down 10%. To illustrate: The additional 5% down is $12,2500. If you had that amount invested instead, and achieved market average returns, that would be $857.50 a year ($12,2500*.07). Your PMI is going to cost you $2,160 every year ($180*12). So your real rate of return on that invested money is -$1,302.50, or -10.5%.
I would probably even say that if you can't swing the 10% now, wait 6 months to buy a house. With your savings rate, you will save yourself out of this dilemma in no time.
One other note--in my experience (just bought house two)--there are always more expenses that come with a newly acquired home than you expected. Unless you have plenty of free time and those mustachian carpentry, plumbing, and/or electrical skills dialed in, just be prepared . . .