Stay away from the 6450 it is not even real 4K. Do a little searching and you will find out on that model. Honestly I would steer clear of either set, Sony or Samsung will make you allot happier at the end of the day.
Current Sets: Sony XBR75X940C, Sony XBR75X940D, Samsung UN65KS9800, , UN55KS8500, UN49JS8500
Previous Sets: Sony XBR65X930D, XBR65X900B, XBR49X830C, Samsung KS8000, KU6500, JS9000, JU7090, JU6500, JU6400, HU9000, HU7250, PN64F8500, Vizio P65, LG 65EF9500, LG 55EC9300, Hisense 55H8C