I really don't get the need for backlit keyboards in this form factor---you're not going to be using this on your lap, in the dark so what's the real loss? And TBH, I personally don't see the huge deal with backlit keyboards at all--but then again, I touch type so not really looking at the keyboard and, I don't like to work in the dark so...
My experience is anecdotal and quite clearly skewed by my personal preferences but, I have both an iPP (actually 2 of them) and a Samsung TabPro S. Both use keyboards that attach in some fashion with magnets and connect via a 'smart connector', so no bluetooth on either. The Samsung keyboard is predomoninantly all stiff plastic, backlit, has a touchpad and is more 'clicky', and allows for 2 different viewing angles.
The Apple smart keyboard is the fabric covered, chicklet style without any backlighting, or function row.
And the typing experience on the Apple version is far more enjoyable. The keys are all flush making it difficult to quickly find the right keys and it's easy to kit the wrong ones.
The keyboard for the S3 seems much more similar to the Apple version so based off my personal experience, that's a big improvment. And like
@The Game 161 mentioned, having a dedicated spot for the S-Pen is a big plus.
All that being said, I still would hesitate to choose this over an iPad if any sort of productivity was involved as I still find Android not a great tablet experience and sadly, Samsung has a history of quickly abandoning their tablets (re: software support). I'll certainly be curious to see anyone's personal experience with this tablet if they do get one.