I have two fretless basses, and on one of those I normally use roundwonds. On the other one I use Rotosouds Black Nylon. I was looking for something in between the two, who had the fat "uprighty" tone of black nylon tape strings but also the brightness and the crispy tone of roundwounds. I ordered these DR black beauties with no further knowledge of how they would behave on my bass, but I have to say I was pleasantly surprised. Already in unplugged they delivered a punchy, fat, yes bright sound. When they went through my 70's DiMarzio pickups I was delighted to notice the consistency with what experienced unplugged. As for the playability, DR black beauties behave very well under the fingers: they have tension enough for my playing, which is kinda heavy (I am first of all an upright player) but yet they are easy to press, and they allow and respond well to all kinds of articulations: legato, hammer on and off, and so on. As for the durability I can't really say at the moment, but I guess they will stay on a long time. If I had to find a downside, which it really is not, is that those are not "all purpose" strings. I wouldn't use them for slap for example, but that is only my personal opinion. Other than that I think that they are great and I definitely recommend them!
I've used DR Extras for a number of years as gigging in a club/function band around 100 times a year I found I was going through lots of strings.
With these coated strings I found that I only had to change about 3 times a year, and often that would be more for cosmetic reasons than tone.
When these strings go on, they don't have the same brightness you'd get from a set of brand new steel roundwounds, they have a crunchy kind of tone similar to a set of nickel roundwounds which have maybe done a gig or two.
They stay sounding that way for ages though. I've had sets which have done 30 gigs and you would never know from the tone they weren't new.
The colour coating does flake a little over time, but not so much that affects the sound, only the appearance. This is more of an issue if you use a pick.
I have one gripe with these which is that DR have recently changed the coating to something called Dragon Skin or K3 and while it may be longer lasting, I find it quite uncomfortable when doing a lot of slides as the friction causes a burning sensation too easily.
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