Like I wrote in my previous post, I did try out some HDR shots on varied lighting conditions and one thing is certain. It works best when there are an array of colors and different lighting conditions over the landscape.
Meanwhile Snapseed ( now a google company) has now introduced an HDR filter which actually performs better than other HDR filters I have tried out in iPhone .
But the below pictures are shot on iphoneHDR and only brightness compensation done either through iPhoto or Snapseed app in Apple iPhone 5
Will post more pictures as I get better with iPhone cam.
Just personal experiences. Not a technical / other advice