According to me there is no any need to tell you about quality of Gmail . Gmail speak itself with it's extraordinary quality from it's launch to till now.Technically you can not create folder in Gmail , to overcome to this problem Google introduced label facility by creating label you will be able to use like your folder ( Inbox and Draft etc.)
Advantage of creating label in Gmail.
In your Gmail account all mail comes into your inbox. suppose you are getting 200 mail in a day. i Will be very difficult for to differentiate you office mail, Friends mail, family mails etc by creating label you can get mail at right place. office mail in one label, friends mail in other label by assigning mail to that label under setting tab of your Gmail account.