They make different metering rod grinds if you need to make adjustments for mid range tuning, your not just stuck with what it comes with.
I have 2 Lectrons on my Husky 177 and Beta 250.
The Husky had a Mukini that would never work from one day to the next, let alone morning vs afternoon with temp swings. Constantly chasing jetting on that pos. Swapped in the Lectron and after minor needle adjustment I have never had to touch it again save for a rod swap to accommodate the big bore/stroker upgrade.
It got consistently better fuel mileage after the swap as well. I bought that carb in '13.
The Beta had a PWK that was jetted pretty spot on, but got debris lodged in the passages and I got tired of trying to get it all out (would end up in the float bowl which would clog up the main jet and cause the needle to hang/throttle stuck open). Other than a float height adjustment, I didn't have to touch anything on that one.
I did have a fuel delivery issue recently on the Beta. It would act like it ran out of gas but then it would start pissing out the overflows as soon as I stopped. One of the floats had come off the lever and was mucking things up in there.
A buddy had a YZ250F with a FCR carb that would never fucking work. Starting it was a chore with a dozen kicks required when cold, half a dozen if you just shut it off normally, and god forbid you ever dumped the bike over and it died. After putting the Lectron on it was a 1 or 2 kick bike no matter what. We did spend a few hours playing with the needle height on that bike though, mostly because we were misdiagnosing what was going.
I had one briefly on a Husky 610 but ended up selling that bike before I put much time on it.