Pros - Feel. Brightness without sounding metallic. Still mellow.
Cons - If you want a "flat" sounding Flat string, these are not for you.
I use the 50 70 85 105 set on fender JB's. Previously, I was using the D'Addario chrome flats and half rounds in the same gauge. Loved both of the D'Addario types, much more expressive than any other flat I'd previously used on my Fender JB's.
These EB's just go a little step further in making the tone brighter. Noticeably brighter, although not by such a huge expanse that you'd be blown away, but you will be pleased if you're after the brightest tone possible with a flat string. They punch out articulate notes without the thud of mellower flats, and sustain beautifully. The resolution between notes when holding arpeggios is one thing that stood out when I first used these.
They feel a little different to touch. More "powdery" smooth than the D'Addario "glossy" smooth. Definitely not sticky or grippy. Sliding along the strings there's an almost inaudible sound, and the cellist and pianist I play with have never commented on string grating like they have from my rounds on a PBass. If you play a fretless, and are worried about marking your fingerboard to the point of being an obsessive freak about that, you may want to take a close look at the strings first as there is a miniscule gap between the windings. But I doubt it would mark the board unless you gave a Tarzan grip (any opinions?).
They've been on my newest JB for 8 months now, and they're sounding just as clear as I think they were originally (the bass itself is still in its 1st year too). I'll be putting a new set on soon (due to a tweaking of set-up), so I'll be able to do a proper comparison of 8 months old versus new, but I'd be surprised if there's much difference. I'll let you know.
Pros - These strings are surprisingly punchy and fat
Cons - A little more than I'm use to paying for regular bass strings, but it was an impulse buy.
I was in Guitar Center looking to purchase a wind screen but they didn't have the size I needed. After checking out basses I browsed the string rack and impulsively bought these Super Slinky Flatwounds for my Jazz bass. I'm pleasantly surprised by the tone. They are both fat and punchy, with great clarity. The strings are very smooth, very playable. I've had flats that took some getting used to initially because they had a tacky feel, but these feel great right out the pack. Exactly what I was looking for. Keep in mind that this is a first impression after 2 days, but I am happy with my purchase.