A little bit of testing how well tar compresses things. I am compressing my blog which is 450mb. It is a mix of mostly text, some images, and most of the size comes from binary files and a debian state file.
tar
tar cvf folder.tar folder --exclude .git
This took 4.25 seconds and created a tar file of 410mb.
gzip
tar czvf folder.tar.gz folder --exclude .git
This took 28.70 seconds and created a tar file of 199mb.
bzip
tar cjvf folder.tar.bz folder --exclude .git
This took 60.85 seconds and created a tar file of 188mb.
gzip is definitely worth it but it doesn't look like bzip is worth it in most cases.