who is better Serj Tankian or Daron Malakian?

They both have different qualities. Both can sing, but Serj's voice is more powerful and distinguishable. Daron is a talented guitarist. Both are composers also. I think Daron used to be really involved in SOAD's production and mixing.

both of them are good, but i like Serj. his voices very strong and powerfull

As a guitarist and occasional back-up singer, Malakian's fine, but his voice is too nasal-sounding to me. Serj's voice is more suited to singing, and besides--I like it a lot better ha. They do harmonize pretty well though.

I think you can't compare people like that, only if you specify the criteria. They both have their good and bad sides, we don't wholly know their personalities, we don't know much about them, so it's hard to give one particular answer to your question.

who are these people? i like system of a down. i'm thinking serj is the lead singer. daron is lead guitar. i just looked at wikipedia. mm. they're all good. they're all beautiful. where are they from? i think they are from ugoslavia. or peru. lol. i don't know. no! they are armenian. i remember. they are cool. their rhythm goes tatatatata. really close together. short and despicable. i like their melodies too. they are close together. really close together. like dadadadadada. a chromatic scale. and this makes them amazing. i don't know who is better. i think they are the same.