Rotosound PN9 Pure Nickels

Long Story Short Version:
They're VERY good, try them.

Long Story Version:
Over 30 years playing I've used just about every expensive string out there, and most cheap ones as well.
These Rotosound PN9 Pure Nickels, for me, are the best.

When using nickel-plated steel strings I could always hear some weird, metallic bright tone I didn't like from the low strings (it took me years to work out it was the strings, and not the pick, amp, or guitar).

Using stainless steel strings sounded more like a Banjo, not a guitar (I played Banjo also for about 20 years, so please don't hate me Banjo players).

Trying Rotosound PN9 Pure Nickel strings was a TONE REVELATION for me.
NO weird, metallic bright tone from low strings.
Much nicer tone (like I always wanted to hear), NEVER had a string break in all the many, many years I've been using them, they last a lot longer than nickel-plated steel before a string change is needed because of dull tone or string wear/gunking up (technical term). They also feel good to play, in a smooth, supple, sexy sort of way (I better stop there before I get deleted).

Stay in tune well. And as well as any other string brand once stretched out.*

Also, those treated paper envelopes that some other string brands come in make my eyes itchy. I mean VERY itchy, as in some sort of allergic reaction.
The foil packets Rotosound strings come in are better and cause NO reaction/itchiness.

Cons:
I have noticed that, once in a blue moon, a set of these strings may need more stretching out to stay in tune well for string bends etc.
Most of the time these Rotosound PN9 Pure Nickels tune up very quickly and stay in tune well, but sometimes I will get a set that requires twice as much stretching out before they give the tuning stability I expect.

Verdict:
Excellent strings. You are basically buying a packet full of TONE.
They feel good playing, last longer than most expensive 'Long Life' strings I have used, never had one break or come undone at the ball end (I'm not going there), and stay in tune.
Also, they are WAY cheaper from Thomann than other places.

If your budget allows, I recommend trying a set. You might just love them.

Let's start with the upsides: packaging is good. Strings seem consistent quality, although they could use a different color for each ball. Stringing the guitar with these was reasonably quick and good.

But now the main issue: playing feel isn't great. These are not very stiff strings and the B and high E strings especially feel too sloppy. Somehow these are missing a nice tactile feel that is needed to get the right feedback for the fingertips when fretting a note and because of that too many easy mistakes when playing.

But strings are very much a matter of taste and technique, and if you don't try them out you can't know whether a particular brand or product is a good match for you.