True, rar does have better compression. The only draw back that I can see is the fact that it's shareware.
size (in bytes) size/type size/type size/type
57,435,478 (2005 version dwg) 49,113,643/.rar 49,975,267/.bz2 51,453,701/.zip
2,312,632 (ascii file) 679,646/.rar 780,115/.bz2 690,110/.zip
Commands used
rar a <file>.rar <file>.ext (didn't see a compression level switch)
bzip2 --best <file>
zip -p <file>.zip <file>.ext
Software used:
RAR 3.30 Copyright (c) 1993-2004 Eugene Roshal 22 Jan 2004 Shareware version
bzip2 Copyright (C) 1996-2002 by Julian Seward. Version 1.0.2, 30-Dec-2001.
Zip 2.3 Copyright (C) 1990-1999 Info-ZIP (November 29th 1999).
Original output of 'dir'
Volume in drive C has no label.
Volume Serial Number is 3447-42B5
Directory of C:\Temp\zip_test
07/20/2004 12:56 PM <DIR> .
07/20/2004 12:56 PM <DIR> ..
05/26/2004 07:47 AM 57,435,478 dwg.dwg
05/26/2004 07:47 AM 49,975,267 dwg.dwg.bz2
07/20/2004 12:21 PM 49,113,643 dwg.rar
07/20/2004 12:28 PM 51,453,701 dwg.zip
11/01/2002 06:54 AM 2,312,632 Unabr.dict
11/01/2002 06:54 AM 780,115 Unabr.dict.bz2
07/20/2004 12:18 PM 679,646 Unabr.rar
07/20/2004 12:29 PM 690,110 Unabr.zip
11 File(s) 310,896,691 bytes
2 Dir(s) 26,925,305,856 bytes free
Original output of 'ls -lh'
total 297M
-rw-rw-rw- 1 pw2n 0 2.2M Nov 1 2002 Unabr.dict
-rw-rw-rw- 1 pw2n 0 762k Nov 1 2002 Unabr.dict.bz2
-rw-rw-rw- 1 pw2n 0 664k Jul 20 12:18 Unabr.rar
-rw-rw-rw- 1 pw2n 0 674k Jul 20 12:29 Unabr.zip
-rw-rw-rw- 1 pw2n 0 55M May 26 07:47 dwg.dwg
-rw-rw-rw- 1 pw2n 0 48M May 26 07:47 dwg.dwg.bz2
-rw-rw-rw- 1 pw2n 0 47M Jul 20 12:21 dwg.rar
-rw-rw-rw- 1 pw2n 0 49M Jul 20 12:28 dwg.zip