The Exynos 5 Octa was confirmed to be LTE-enabled and that it supports all 20 bands. This bit of info was taken from the SamsungExynos page on their Twitter account. This means that it can also do what the Snapdragon 600 (Qualcomm) is capable of doing. However, there are also reports (fom SamMobile) that the reason why the Galaxy S 4 came in two variants is that Samsung was unable to deliver the Exynos 5 Octa in time for the S 4 launch.
Furthermore, Samsung actually confirmed that they have just started mass producing the famed chip after the first quarter. According to the reports, only about 30% of the total Galaxy S 4 production have Exynos 5 Octa in their hardware and many are hoping for more Exynos variants to be distributed in the near future.