Mathematically, how important is advantage on concentration checks?

I’m playing a pact of the blade fiend warlock in a game that just leveled up to 5. I’ve had the Eldritch Mind invocation since 3,but it has only actually saved me on one or two occasions so far, the most recent occasion being when I got hit by a wyvern’s tail and took a massive chunk of poison damage. To be fair, this is partially because our game doesn’t have a ton of combat encounters, but when they do happen they’re often very dangerous.

Because eldritch mind hasn’t come in clutch too often, I’m considering swapping it out for something a bit more fun, like perhaps One with Shadows. I’m also aware that if I wait until next level the fiend patron’s 6th level feature can help out with concentration checks. I’m hesitant to do this, however, because I keep going back to the instinct that advantage on concentration checks should be REALLY GOOD. So I wanted to know exactly what I would be giving up here. Worth noting my con mod is +3