I have also been an owner of an Apple iBook 2001(aka icebook) similar to the one mentioned in the article. I ran SuSE Linux on it while I had it. Great distro, easy installation, and knowledge-base support for any issues.
While I do not disagree with the article itself, I should mention a couple of non-linux related issues from my experience:
My verdict is that the iBook is a good solution 'as is' if you do not plan to manually expand it in any way. The only 'easy' thing that you can change on your own is memory, and for that you have to dig quite a bit under the keyboard. Other components, notably the HD, are almost out of reach unless you really know what you are doing...
So for any new components (apart from memory), and to avoid voiding your warranty, you must ask for support by official Apple engineers, and to accept whatever HW Apple supports (you cannot add *any* HD or RAM modules for instance). This kind of dependability proved the reason that I got the iBook returned after 5 months, getting a refund.
On this support aspect you should also be aware that quality of Apple support varies from country to country. In the UK, where I am, it was the worst nightmare: the machine went to Apple in perfect order but came back within 3 months (!) after the initial 'check-in' with Apple and horribly deformed (surface was scratched beyond expectation). A single case? I am not so sure about that. Check local newsgroups before making any move to get the iBook, no matter how 'sweet' is the pill that they offer.