According to one Hadith Prophet SAW even refused to see two men whom's beards where removed. From this we can understand how Important it is to keep the beard that our beloved Prophet not even seen the faces from whom beards where removed.
Beard also distinguishes the males from females and men who imitate women have been cursed by Prophet Muhammad PBUH and it has been rightly said that a man without his beard is like a lion without his mane.
Many Muslim men criticize scholars who highlight the importance of beard by saying that Islam is not in beard but they have to admit that there is beard in Islam and it is very important Sunnah.
as far as the size of Beard is concerned there is also Hadith about it. Prophet SAW said Cut the moustaches short and leave the beard (as it is). So according to this Hadith we should leave the beard no matter how much it grows. However those people who keeps smaller Beards are still better than those who completely shaves the beard. May Allah SWT help us all to follow this important Sunnah of Rasool Allah SAW.