Thana Jordan wrote:
> how big is it to download netbsd incl. source code.

A quick look at ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-2.0.2/i386/ suggests 
around 100 MB.  You could probably find an unofficial CD-ROM .iso image, too.

> how big is the packages collection

About 6000 entries.  If you installed them all, they would probably require 
somewhere over 10GB of disk space.

> can anyone explain the benefits of installing packages from source over precompiled binaries

Sure.  You can change compile-time options, compilation flags, and build the 
software exactly the way you want it to according the what else is on your system.

-- 
-Chuck