Works great for me! I use my rooted HTC One running SWG 4.3 and my Sprint Galaxy Tab 3.0 stock (can't remember what android version) and use my laptop as well.
At home, I tether with my HTC One on LTE with no lag at all while casting local files from my Tab 3.
I even tried my chromecast at a friend's place and played all local photos, videos, and music from all my devices on his network without lag and any issues.
Sent from my HTCONE using xda app-developers app