Mine is the Sprint LTE model. It had split screen from the beginning.
It's a complete new feature for those of us that bought the WiFi only model. I was rather surprised to see Samsung add such a feature to what is pretty much a entry level tablet.
I still can compare it to my much older but better built (and designed) BlackBerry PlayBook which with older hardware can capture full 1080p video from either the front or rear cameras with stereo sound but for overall features in the OS (now with 4.4.2), the Galaxy Tab 3 7.0" has finally felt like a modern tablet but still with some weak points. The cameras are just as bad as my much older iPad 2 which almost could be a good device to compare with but it and the PlayBook were premium devices for their time.
The PlayBook doesn't lend well to portrait use like the iPad and Tab 3. It's also like the others now, obsolete not seeing an update in ages and very hard to come by. The iPad is everywhere you look and it being years older than my Tab 3, Apple still supports it even with the latest iOS release. Not too shabby for a very dated device that somehow still is able to perform better in gaming with much older hardware. I'd say I got my money's worth out of it after several years and going big with the 64GB model.
Now with my Tab 3, it's the only one that supports 64GB SDXC memory cards. The Tab 4 series of the same device level had SDXC card support removed for some odd reason. It makes me appreciate my meager WiFi only model of the Galaxy Tab 3 series a bit more as it sounds absolutely fantastic with a good set of headphones or even ear buds.
So my point is while we waited for Samsung to deliver on their promise of a modern OS update and for those that have the simple entry level model like my own, I'm pleasantly surprised to see new features added to such a device that Samsung could have easily ignored and moved on.
It runs smoother overall and it's just a great tablet for doing basic tasks but also has some good gaming ability too. It's not going to smash a quad core model nor a Nvidia Tegra equipped tablet, but for general purpose, I think it's fantastic now running Kit Kat with a 64GB Micro SD card in it that plays music amazingly well but also a great machine for watching movies too.