I am a OS X user, and I am also a Linux user. OS X packs FreeBSD user land, Linux packs GNU user land. Somehow I managed to like OS X, but also GNU user land.
That is why I am always trying to replace my OS X FreeBSD user land with GNU equivalents. That will involve some heavy-duty compiling and checking. Tiring, but rewarding as my scripts can work on both systems.
One missing piece I tried to port but never succeed is Ubuntu’s bash-completion package which is makes bash super easy to use.