Summary: I bought this one a year later to replace the UX31A-DB51 that I sent back 2 weeks after buying due to faulty keyboard and track pad. The UX31A-DH51 is awesome, bought it in Feb 2013, no problems. Runs like a champ. Though I only use it for light word processing and nothing else. I still have my work horse machines for the heavy lifting. Both are core i7 with 8g+ or more of RAM, 1g+ discrete graphics cards or more; one is a Desktop the other is a 5lb laptop.
Summary: i bought this for the purpose of making an Ubuntu ultrabook for programming with. excellent choice. it came with windows 8, which i replaced with 12.04 LTS. very easy install, all the hardware worked. the next day i decided to upgrade to 13.10 upgrade process was smooth, went to 12.10, then straight to 13.10. no issues. 13.10 runs great on it, and i haven't noticed any problems with compatibility.
Summary: This Asus UX31A-DH51 is my best laptop ever. It beats my wife's $1k+ Dell laptop easily. This Asus is lightning fast on boot because of the solid-state drive--128 GB is plenty of storage, too. I travel, and this laptop is a good traveling companion. It is rugged and beautiful. I use my ham radio internet remote base on this laptop--it is very stable and the audio is superb. I had initial problems with the touchpad. After I updated the drivers it is rock solid.
Summary: Excelent value and performance dollar for dollar, extra slim design. Great quality in its construction. I have an HP with same characteristics and Asus outperforms with exception of batery life time.