which airline is better eva air or singapore airline?

Singapore Airlines is better with no doubt as Singapore Airlines is a five star airline by Skytrax (the official rating organisation for airlines and airports). Singapore Airlines has good service and new aircrafts such as A380 and every aircraft in Singapore Airlines have personal TV Screens but some aircrafts in EVA Air do not have personal TV screens such as the MD90 series and EVA Air is only a four star airline.

Go check this website if you want to know more :D http://www.airlinequality.com/

Hope this helps

With a lot of details? Sorry there's not enough place here to write so I'll redirect you to much greater level of information:

http://www.evaair.com
http://en.wikipedia.org/wiki/EVA_Air
http://www.airlinequality.com/Forum/eva.htm

http://www.singaporeair.com
http://en.wikipedia.org/wiki/Singapore_Airlines
http://www.airlinequality.com/Forum/sia.htm

http://www.flyertalk.com/forum/other-asian-australian-south-pacific-frequent-flyer-programs/1099178-eva-elite-b777-300-versus-singapore-airlines-economy-a380.html
http://www.fodors.com/community/asia/singapore-air-or-eva-air.cfm