Numerous users report that despite being a Chinese locale, the firmware appears to be authentic. At the time of writing there have been no major bugs found - Wi-Fi, 3G/4G data, NFC, Bluetooth, all sensors, and everything else you might think of seem to be working fine. Still, as we mentioned above, certain system messages will probably appear in Chinese, but that's a price that the eager early adopters of said leaked distribution will have to tolerate.
The build reportedly only works with several versions of the Galaxy S4 - GT-I9500, GT-I9502, GT-I9508, and the GT-I9508v ones, with the notable omission being the Snapdragon 600 variation, the GT-I9505 variation of the former Samsung flagship.
Provided that you're using a Galaxy S4 and can't wait any longer, follow the source link and give this Lollipop build a try. As usual, make sure that you have a handy NANDroid backup in store, you know, just in case something goes wrong.
Meanwhile, the Galaxy S5 already took a lick from the TouchWiz-esque Lollipop that Samsung released and we quickly compared it with the older KitKat firmware. The Galaxy S4 will, most probably, receive its own Android update pretty soon.