It's not a matter of "I mean, yeah, form factor", but rather "Form factor!".

The form factor is pretty much the defining characteristic of the Nitrus. A lot of Karma features are not present on the Nitrus because they simply won't fit.

To my surprise, having something this light and portable, but still able to hold a reasonable number of tunes (i.e. enough to keep you going for a whole day) is very appealing. Especially if your normal mode of listening to your collection is "Shuffle the whole damn lot, and then I'll skip any I don't like". For me that's true about 95% of the time.

And Rio Music Manager does a reasonable job of automatically rotating the material, so you don't get have to manually swap things around when you get sick of what's currently on your player. (Obviously extra capacity and processing power would be nice, but as my grandmother used to say "You can't make a cake without breaking a few legs" (sic) .)

So at the moment I'm in a bit of an unexpected quandry as to whether I want to buy a Karma or not, because I really like the ultraportability of the Nitrus.

Richard.