Looks at how it compares to a new phone that's bring touted as the best.
http://youtu.be/oE8jHskLNfQ
^^ Comparing the S5 to my Note 3, IMO what this video shows as "lag" or delays is simply the animations within the OS for the Phone. I've turned off all three animations and those very slight delays are gone completely.
Thus I think it really depends on what type of experience users are looking for. I like rapid fire response vs the slower more animated launches.