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.
Ernie Ball Super Slinky Flatwound Bass Set, .045 - .100
SuperBright Cobalt Ribbon - Superior Sheen and Feel Cobalt Under wraps - Added Clarity and Output Optimal Core to Wrap Ratio - Comfortable Tension