I have no experience with locking Sperzels, but my current favorite guitar(s) are Strat Plusses, which came (originally) in their very early years of production with Sperzels, then switched to Schaller locking pegs. I consider these guitars to be incredible deals, if you can get one with low fret wear and made after 1993 with the LSR roller nut. The frets on the guitars are installed in a different way than other Strats and they are simply outstanding.
But I DO have experience with Mr. Sperzel, and if you send him that tuner, he will replace it.
I have not encountered Sperzels, because another change these Strats made was to switch to an LSR roller-nut and away from Wilkinsons. This they did in about 1992. I like LSR nuts MUCH better, and I understand the Wilkinsons aren't made any more.
OK, so that said, I have two of these guitars and thus two sets of locking Schallers. They, too, sometimes experience the internal pins getting jammed in the string capstan. I was able to free it up just by taking a (wound) string-end and diddling the pin back to the "open" position.
Now. One of the Schallers on one set of tuners developed a truly annoying "flat spot" where I could not get a linear adjustment and thus could not get the thing to tune. I had to replace it.
On the other guitar, one of the tuners is very hard to turn, even with the screw through the key backed off quite a bit. So there is something hinky with the gears inside the thing.
My point, I think, is that this new-fangled stuff isn't always the be-all end-all. I probably have had a dozen sets of Grover rotomatics that never gave me any troubles at all. Here I have 2 out of twelve tuners that are funky, one of them beyond being usable.