A well made ranger will wreak havoc and in most situations where the opponent has huge defence rating/armor he still has enough tricks up his sleeve to be competitive.

That being said, every "class" when build properly can do pretty insane stuff.

http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=539712#Post539712 to go more indepth of archer.

Don't have to much time sadly otherwise would love to elaborate.

Ciao ciao!