Hi N L
First, you don't really want a Steinway S. The problem with that piano beyond its exorbitant price is that at 5'2" it's a true baby grand. If you're a serious pianist, you need a grand at least 5'5" in length. A medium grand (about 5'8") or a larger parlor grand (about 6'3") would make you far happier. So the 5'10" Kawai is more along those lines. An RX-2 in white typically sells for $29,590 according to Larry Fine's book, but dealers do discount further. So a brand new one for $14,000 it sounds like a steal. Kawai RX grands are considered to be consumer grade grands, not high performance grands. Nor are they considered ideal for performing classical music.
Personally, I don't like Asian pianos as well as American and European brands. I do like Kawai more than its chief competitor Yamaha though. Kawai to my ear has a richer sound and seems more consistent throughout its scale. The thing I dislike about Kawai is that it lacks a "signature timbre" that would give it an unmistakable character. Instead, it's has a neutral or plain vanilla sound, at least to my ears.
Yes, Kawai is a very reliable piano. It gets fine factory preparation. Warranty service is very good, and after-sale problems are generally limited to very minor problems.
Where the price is so dramatically low, I tend to think "if a deal sounds too good to be true, it probably is". So you might want to have your own technician check the piano out to make sure there is no hidden surprise in there. Also ask about the details on the warranty, which should be a Kawai Company warranty, not a dealer warranty.
Good luck on your search for a piano!
"Interpreting music means exploring the promise of the potential of possibilities." David April