My whole yard is Zoysia and I absolutely LOVE it!!! I built my flower beds then laid the Zoysia down myself when I had my house built and I'd highly recommend it although those advertising claims you posted are overexaggerated. Don't mess with seed, save yourself some trouble and just get the Sod. Everyone here has Burmuda so Zoysia is the only grass I could think of that won't get choked out. It does VERY well, it's thick like carpet, very pretty, and only needs to be mowed twice per month. This is an old pic of mine almost 1-week after it was last mowed. Oh, and yes it doesn't get as many weeds because of its thickness but it does still get a few here and there in the low spots.
