Good. Great even. If the implementation is top notch, mantained and from the 1st party, why the hell not, but most of the times, language server implementations are half assed, slow, "kinda" working messes that are all but useless in the long run. The PHP language server implementations are a great example of this. A buch of broken, incomplete, underperforming projects maintained by a single person (or straight up abandoned). Compare that with Phpstorm and you have just compared a rusty tricycle with a spaceship.