This question was asked to me by one of my friends last Saturday. In my opinion, it is safe if you have a car but if you'll commute everyday, it's not safe especially if you used to ride the Gate 3 jeepney. Even though there's a Philippine Army in McKinley Hills.. still it's not safe.
Last June 2009, I had a bad experience riding a Gate 3 jeepney from McKinley Hills going to Market Market. It was around 7pm, I was patiently waiting at the Jeepney Stop. Fast forward. Inside the jeep, there's a man in front of me kept looking at me. But when I look at him he would quickly look at the other direction. Observing his behavior, I have a hunch that this guy is a holdapper. I went down the jeep at Market Market's open fruit section, but still observing if the guy will follow me.. and he did! So I walked fast towards McDonalds and he kept on following me. Good thing there's a Security Guard! I told the security guard regarding the guy. And when the guy noticed that I reported him, he disappeared from the crowd. I informed my family regarding the incident and waited at McDonalds for 30minutes for the arrival of my cousin and brother-in-law. Thank God I'm safe. To describe the guy, he stand 5'6 to 5'7 in height, medium built, brown complexion, wavy to curly hair, round face with round black eyes.
My teammate has a share of bad experience commuting at McKinley Hills. He was holdapped last 2009 around 11pm while riding the Gate 3 jeepney. He gave his new mobile phone and his wallet. Good thing the holdappers didn't hurt him.
Another story from my team lead, dated July 19, 2010, 10am when he was going to the office at One World Square. Inside the Gate 3 jeepney, he witnessed a man put a bubble gum to one of the girl passengers. They kept convincing the girl to remove the bubble gum from her hair; the man in front also offered his help to remove the bubble gum. But the girl ignored all of them maybe she knew the bubble gum modus operandi.
If you're commuting to and from McKinley Hills via a jeepney, you should be Alert, have a pepper spray, go home early and always pray to God for guidance. ;)