These strings are of course flat and are also coated with black nylon. This may not be for everybody, but I had them for over a year (without any sign of wear) on my Squier 40th Anniversary Precision Bass (Classic, with the maple neck and fretboard). I am reasonably experienced (I played for 50 plus years and I like prog rock, blues and any kind of well made music from Abba to Zappa)
The word is ‘smooth’, both in sound and feel and for some of us who might play the occasional heavy metal or hard rock tune, these strings are too weak. But beware! I am talking about a (surprisingly good) Precision and you could be playing a totally different instrument with active circuitry. There is only one way to compare your experience with mine: try them! I usually play poppy stuff, country, ballads and jazzy walking bass lines. These strings make me happy, while they provide deep warm support for my singers without putting themselves to the foreground. Nothing wrong with that, but then you may need round wounds.
Oops, I now see I was talking about the 4 string set. I have also used the black nylons on a Yamaha 5 string bass. I remember I found the B-string a bit too loose. Anyway, I stopped playing the 5 string bass, but what I wrote here about the black nylons is to me still true.