Definitely useful and I think it compares pretty well to other tooling? My two biggest issues are compile times and "amnesia". First of all, compile times because the feedback cycle can get really bad. But that's not really rust-analyzer's fault, that's cargo/rustc.

But rust-analyzer also has this weird "amnesia". Like if I have ran the checks and everything is good, I can go to definition and it will instantly bring me there. But if I make a small change and it starts running cargo check, it's like it forgets everything until it's done with cargo check. I wish it still allowed me to use what it knew before and go to definitions and give suggestions and such.