Before you trust someone with your nice instrument, please make sure they know what they are doing.
I have bought many extremely cheap guitars to donate to my local charity programs.
I would always at least change the strings or try to make the instrument more playable so the kids who eventually get it would want to play it.
Fender rolling nut is one of the rare times Fender admits they actually could have done something better, but presented as an option.
It is like a circumcision for your guitar, almost impossible to roll back.
You need to CUT INTO THE NECK and remove a few millimeters of the actual fretboard to make it work.
Needless to say, a botched job can ruin your instrument and make it impossible to intonate, or otherwise sound completely different.
However, if you have a luthier you trust, as I do, speak to them about installing this nut (permanently) into your instrument, the advantages and any fears they might have.
Any alder body strats or teles are a no brainer...
Fender should just install this by default, but it would cost a few hundred more....
Obvious benefits are tuning stability but sustain is even more pronounced.
The tone is finally the same on all strings, forever.
My test guitar for this was one of my favorite guitars, Shiva, a 1999 fender stratocaster with an ash body and rosewood neck. It has been with me for 25 years so I was sure I wanted to take it further with a VERY trusted luthier.
He has worked on Shiva before and knew what I was looking for.
It is outstanding.
I am planning to install this in my two remaining strats (both are ash and maple necks).
This is not to mention that, should I ever want to change the string gauge, I´d have no issue whatsoever. Great, great upgrade, just have a great professional install it!