Ok, not all shitty once it actually works, but there's a problem with it's software (drivers) or wireless hardware, atleast in combination with my Netgear router.
With WMM enabled, things are really shitty... The Squeezebox shows meta information and browsing the directories is almost not shitty. It's experiencing general slowness and lag. Response to Squeezeboxserver remote commands are kind of random. And audio just doesn't play at all... On one occasion I saw the "Buffering" message reach a staggering 2%. Wow, that's only 98% shitty!
So, turning off WMM (Wireless MultiMedia extension support) in the router seems to fix the issue.
I've never had a problem until now with this on any of the 10-20 devices that's ever been hooked up to my router.
I'm going to say it again, if you have a similar wireless issue on your Shitty Logitech Squeezebox Radio - turn of WMM in your router.