Selling our Four Plex

I keep seeing sale prices for 4 plexes in our area that are very attractive.  I've calculated our expected rent, paydown of mortgage, and cash flow, and determined this is a good time to sell.  It might be the most opportune time in quite a while.  We bought the building three years ago for 295K, and have put $30K into it.  We've cash flowed about $1500.00 a month the past three years, so we've made about $50K in profits on rent, and will be offering to sell it at $425K, which is roughly 10 times current monthly revenue.  We expect to clear $150K, of which we will use between $50 and $100k to 1031 into other buildings.  

Just a quick note. It is very important to your sale price to maintain your building well, and keep your rents to market.  Other, beat up buildings in my area have sold for as little as $320K, because they did not keep their rents up, which impacted their building maintenance.  

If it doesn't sell for our asking price, we will keep it.  Hard to see a downside here.