The Edge and MKX are exactly the same car. Like everyone else has said so far, the 2007-2008 Ford Edge and Lincoln MKX were very unreliable. The engine was known for stalling, the $3,200 transmission is prone to failing, and the funniest issue is that the tailights and turn signal bulbs are known to melt and some have caught fire. Many people buy this car because it had cool styling for the time. Don't fall for it for these years.
However, the 2009-2010 Edge and MKX were reliable. 2011-2013 had door sensor malfunctions, which is very annoying, but not a safety problem.
My top alternative would be a Toyota Highlander, though it may be hard to find one in your price range. They are the most reliable. Every year.
The Mazda CX-9s were reliable during 2008-2015. The CX-9 is based on the Edge, but as Consumer Reports says, "Overall, it is a bit of a hidden gem. Based on a stretched version of the platform of the Ford Edge, the Mazda is quieter, more agile, and has a nicer interior with attractive trim." In 2007, Mazda used the engine and powertrain from the Ford and instantly had problems. The next year, Mazda used their own V6 powertrain and the problems vanished. The #1 problem is a brake booster failure, but it only costs $500 and Mazda extended the warranty coverage for it.
All Honda Pilots 2006 and newer are reliable, too. Don't go earlier or you'll have a failing transmission.