I already bought discounted deals on these online deal sites: Deal Grocer, Metrodeal and Cash Cash Pinoy. If I have to choose what for me is the best deal site, among the three Deal Grocer has my vote. But based on experience, I (without a doubt) place Deal Grocer on the top spot.
Metrodeal gets a negative vote from me. I had problems with some of their merchants but they never, ever helped me contact those merchants. They ignored my tweets and they don’t have any contact number on their site. I reviewed one of those deal-gone-bad at Eatallyoucan.info (when you get to the site, search "Apricot Diner").
Nothing to rave or grunt about Cash Cash Pinoy. I never had a problem with them but their deals are not as good as those offered at Deal Grocer. I haven't tried Groupon yet, I wonder if I'll be a happy and contented shopper there as much as when I buy and use my vouchers from Deal Grocer.