I owned a iBook for 4 years and it has been great, a buddy of mine actually bought it from me recently; 1.2 Ghrz G4, 1.xx GB ddr2, 60 gb HD, 32mb GPU. Now keep in mind things are "slower" on old computers only because at you have experienced something new and faster. It never gave me any serious issues or acted up; yes sometimes you might have to power cycle them (macs) or something else random might happen, but that happens with any computer. Our shop alone has gone through 12 different PCs, 10 Macs, and countless printers. I recently purchased a MacBook Pro for my return to college and have been pleasantly surprised with it the entire time.
Now, yes.... the components that make up a Mac are the same as with PCs; BUT...............You pay for far far far far far far FAR less sh!t. Virus? ha.. Malware? ha.. Spyware? ...no.. "Oh but you just run software to clean.." Yes, but how about a computer than doesn't NEED that mommy care? Macs are not upgradable like most PCs, laptops obviously don't count. Macs can do anything (damn near- everyone can find a loophole) that PCs can, granted they are not the best for gaming unless you step it up to a higher end model. The feel of a mac is different than a PC, but it's all software related aside from a couple keys. I think if you're open minded about computers and not all "I know html...mmm...C++....mmm DOS monkey.." You'll be just fine; think of it as a new game console...just gotta get the hang of it.