It could be Qwickster, Quickster, Qwikster, Quikster, Qwickstr (if you wanna go the Flickr route) and probably some variations I haven't thought of. At the very least, Netflix should have made an effort to secure the domain-names for these alternate spellings to ensure their customers can find them when they finally go live.
The other other difference is that iPad, iPod, iPhone, etc. actually describe their eponymous products, and Qwikster doesn't recognizably describe anything.
iPhone? Sure. iPad? Maybe. iPod? Definitely not.
It only seems that way because the iPod dominated the product category so strongly as to become synonymous with "portable digital music player."
Same thing for iPod. It's pod-shaped (or was when it was introduced) and it's a pretty simple mental leap to classify this "pod" as a thing that you put your music "into".
By stark contrast, "Qwikster" has absolutely no mental, cultural or conceptual link to the product or service it describes. It's worthless as a name in addition to being confusing, already taken by various other services, impossible to spell, and dorky.
Not really debatable.
Not saying I like "Qwikster," but it's just not the case that the word "iPod" sounded like a music player before Apple made it famous.
And the correctly-spelled Twitter name! http://twitter.com/#!/qwikster