iriver h120/h140 have both analog and digital in,
iriver h320/340 only have analog in (but have usbotg)
both are well supported by rockbox.
the h1x0 ones have monochrome display, the h3x0 ones are color.
although I've touched a h1x0, I get the feeling the 3x0 keys are harder to click by accident than the h1x0 joything (I've never used 'hold' so far)