Yoona's voice is too plain for my liking. While Hyoyeon's voice isn't the best I really enjoy listening to her singing and her rap is pretty good too.

At least when given suitable lines, Yoona sounds better

^agree Yoona sounds better

actually, both are terrible (no offense) but Yoona sounds better~

Yoona has many fans than Hyoyeon

but this isn't about fans..

it still irks me to see Yoona singing more than Hyoyeon overall.... just because she's the visual, she gets extra lines and that's stupid and unfair to the people who are actually better. Hyoyeon has a very unique voice and a decent control. Yoona is just really bad, period

^yeah~ agree with you in the unique and control and it also irks me that Yoona gets more lines but the problem is with Hyoyeon (just saying) is that some people don't find her voice attractive when she sings~

^^
Agree

Yoona's voice is better than Hyo's I think. Neither of their voices are ever shown off by giving lines that perfectly suit them. But i think 'the boys' really showed how Yoona can sing and rap. Hyo's voice style is more than rapping and no offence to her but it sounds like she needs to clear her throat before singing.

Singing isn't either of their strong suits but Yoona sounds nice when she's given a part in her range. And tbh Hyoyeon's voice is kind of grating.

Yoona's voice is probably the weakest in SNSD. Hyoyeon is definitely better than Yoona. Although both have subpar techniques, Hyoyeon seems to be more consistent in lives, although it's quite hard to determine as both only get about one or two short lines in songs. But Yoona really impressed me in The Boys, although she sang with backtrack.

agree with Miyuki-hime