There's no delay "issue". It's a deliberate design, with the idea to provide a more realistic legato behavior. There's also a "classic" legato version that has considerably less lag in favor of a more immediate play feel.
I mean "better" is a broad term. CSS is just great at what it's aimed to be: a no-frills, workhorse, versatile, go-to, absolutely charming sounding strings library that's easy to use and produces good results quickly. Obviously it doesn't come with a bunch of esoteric and weird articulations (CS ponticello played with the teeth and all that jazz), so it's not gonna be the right choice if you place huge value in that sort of thing.
I can't really think of any clear drawbacks, honestly. It might be somewhat limited if you're looking for extremely soft dynamics. It also doesn't have the "I'm stacking 12 string libraries on top of each other" or "we definitely need 36 celli here" trailer and superhero sound. Some people might find the vibrato a bit on the schmalzy side at times. Some people felt it sounded a bit too dark (can be very easily "hyped" with a few dB of a nice, broad colored EQ).