QuickTime can't play 4k video while VLC can
Let's be honest : appart of the UI, Quicktime X a crapy software in term of compatibility. And it became crappier since the development of Perian has stopped. And on Mavericks it's even worse (Perian doesn't work anymore ...). The cause : QuickTime X is based on the AV Foundation Framework which is only powerful with H.264 stuff (yeah the file format sold on iTunes). 

VLC is powered by a different video library than QuickTime and it's know to be one of the most compatible player yet. 

TLDR: So no there is no there is no solution yet. Let's hope the situation will evolve.