facebook is better for get some backlinks

Both sites are increase your traffic, so both are important in seo.

both are good..
but facebook better than twitter

Both are best to the seo. but facebook is more best to the seo. because you can like page to your friends and your page rank is increase and gain your traffic, visitor on your website.

Facebook is Best

both are good but face is better than tiwtter..

facebook
 

From seo point of view i think face book is better than twitter..

I like both but suggest you twitter. Because you can increase billion billion followers here that really help you promoting your business.........

As per me, Both are really helpful to have better web presence. It helpful to generate a leads to your business.

Both can be very useful if one can use them properly .

Both of them, they can take traffic to your websites and make your sites popular. Popular sites are easy to improve rank in google.