I think it sounds nice, and kind of sexy, all slippy and slidy, with just a bit of nasalized vowels (í) . Lot’s of šs and slchts and čs. I disagree that it sounds like German or Russian…perhaps somewhere in between.
It sort of depends on dialect; the Prague dialect is kind of sing-songy, yet to me sounds kind of “foreign” as I don’t live in Prague. the “ej” endings of adjectives, as opposed to ý endings out where I live, sounds really weird to me, like how I imagine a Texan sounding to a Londoner or something. Even though geographically the reality is quite the opposite.
Out here, the accent is more throaty and less nasalized, but also less varied pitchwise.
The intonation can be pretty monotonous, something which is turned up to ten when a Czech speaks English. I know: my wife is Czech and sometimes I just marvel at how long she can go on talking without varying pitch or tone at all. English speakers usually only do that when we are trying to sound like robots, though I’ve known a couple English speakers who spoke like that. I was a teacher so I have a pretty good speaking voice and for some reason I’m hypersensitive to this kind of thing.
But you don’t notice it so much when you are hearing Czech, it sounds more natural then.