I've never had a problem with the three differnt iPod's I've owned. I even bought one for my Dad for his birthday as well as one to run the hold music at my work.
They are great little mp3 players, The only bad things I've heard are anti-apple sentament and alike.
The most common complaints:
They Scratch eaisly
Every MP3 Player I've ever owned has scrathed eaisly. Buy a little mylar protector for the screen, Adds an extra $10 but you eliminate the problem.
The battery doesnt last very long
Most MP3 Players with rechargable batteries dont last all that long. Given the iPod lasts someone less then other, Still, 10+ hours is more then enough for the longest plane ride. If that doesnt suffice, Just pickup an external power adapter or battery pack.
Your stuck with iTunes
It works. I cant say that about the mp3 players I've owned and there software or wmp. But if your really adamently aginst iTunes, You can always use winamp with a iPod plugin or if your using Linux, Banshee has native iPod support.
You can only buy music from ITMS
The iTunes Music Store is the largest online music store (for downloads that is) and has the best (if not close to it) pricing out there. Besides, the other services still restirct you to approved mp3 players which are ussually as expensive as an iPod. It's the whole Gillette Razors business model. Give away the razor, Sell the blades.
iTunes screws up your music library
Not if you tell it to leave your music alone. As long as your entire library isnt in WMA format, iTunes wont touch it. Besides, Even if it does, It's keeps everything nice a clean as well as properly organized.
I still recomend the iPod, Being the most stable and robust (Mine runs Linux
) mp3 player I've ever toyed with, I really wouldnt go back to the other companies. They have 80% of the mp3 player market share for a reason, and it's not because the iPod is fashonable. It's because it works.