So I have the 2013 11" 4GB 256GB GM... it went from average 6h to 10h with my usage pattern ... M$ Office suite web surfing email ... NO FLASH ( have it blocked+Ghostery+Adblocker .... it has reported on some occasions 14h !!! and have used it quite happily for 4:30 hours already on this charge and still reports 5:21 remaining ..
This is not my heavy lifting Machine (Mackbook 13 rMBP) this is my use in the evenings on the sofa .. lets check emails and stuff (replaces my iPad Mini ... still prefer the keyboard when editing excel ! and Powerpoint)
your milage may vary ..
I am also seeing a ~2:30h increase on the rMBP ... used it all day at work yesterday and still had 40 mins of battery left when heading home .. usually need to charge it sometimes in the afternoon..
Tip I used intel power gadget to identify apps and services which would not allow the CPU into the lowest power state.. So I had to remove on both only Cinch and
the previous version of the Displaylink USB display driver ... here version 2.1 beta helped to allow the deepest power state for the CPUs and thus saving power .. again your milage may very