Most Ultrabooks in the local market have ditched the SSD drive in favor or a hybrid (conventional hard drive + SSD cache drive) in the interest of keeping the cost down. Looking at the available options right now, if you want an Ultrabook or Ultrabook like device, you have Apple's MacBook Air, Samsung Series 9 and Asus new Zenbook Prime as your options with an SSD drive installed by default.
The Asus Zenbook Prime UX31A-R4003V is a fairly expensive notebook, at Php69,900. It is cheaper than Samsung 9 Series Ultrabooks and the Apple MacBook Air with a 256 GB SSD which are priced at Php76,900 and Php72,900, respectively.
With a 13.3-inch screen the Asus Zenbook Prime UX31A-R4003V is a direct competitor to the 13-inch MacBook Air (256 GB). Between the two, the Asus Zenbook Prime has the edge in hardware.
The Asus Zenbook Prime UX31A-R4003V comes with a Full HD IPS (1920 x 1080) display, as compared to the lower resolution 1440 x 900 display on the 13-inch MacBook Air. If you ask me, a full HD display on a 13.3-inch laptop may be too much of a good thing but I will concede that it does allow for playing Full HD content in its native size and makes pictures look sharper. Please note that some lower priced Asus Zenbook Prime UX31A's come with a 1600 x 900 display, so check the specifications well before you purchase if you want the 1080p display.
The Asus Zenbook Prime UX31A-R4003V also comes with a faster Intel Core 17 processor, a 3157U which is faster than the Core i5 unit you find on the MacBook Air.
The other specifications of the two are nearly identical with similar size and wright, both with 4 GB of RAM, back-lit keyboards, USB 3.0 and Bluetooth 4.0. Both have nearly identical battery life. The main differences are in the ports. The MacBook Air has a Thunderbolt port while the Asus Zenbook Prime UX31A has HDMI out. The Thunderbolt port is more impressive in terms of technology, but HDMI out is more useful in real world use. Not that many Thunderbolt compatible peripherals in the market. Plugging a MacBook Air to your LCD TV still requires an adapter.
Of course, the other major difference is that the Asus Zenbook Prime UX31A-R4003V runs Windows 7 Home Premium, while the MacBook Air runs on Mac OSX. I think, this will be the major factor in selecting which among these two you prefer.