This is a well written even handed treatment of Groupon. I guess the other "con" I have heard is that it takes a while to get all your money from Groupon. Of course there are no shortage of daily deal sites out there, but groupon and living social are the main ones. In our area there's on called "seize the deal" that gets a fair amount of traffic.
Servicevines is an outdoor marketplace where Pro's and customers meet and fall in love.