The main thing preventing you from eating soft-boiled eggs out of fancy cups every morning.
Note: I haven't actually used this version, but I had its predecessor (maybe get a warranty from square or something since there may be reliability issues?). One major benefit over a dedicated egg cooker is just that so many of them have a loud buzzer that you can't disable!
But I'm also convinced that toaster ovens are preferable to toasters for most people, so if you pick out an egg cooker that you like, let me know and I'll add it here.
Also: I've heard that the Instant Pot does a good job with eggs (but it seems unwieldy for making a couple soft-boiled eggs for breakfast)