I'm an absolute ho for mysteries in various media, and while many other games can mimic the aesthetics of a mystery story, Eureka is the first one I've encountered that's genuinely designed to enable investigation as a core feature of the gameplay. The Eureka mechanic is phenomenally well-designed to prevent the "banging your head against the wall" problem that can come with failing checks in an investigation, and the emphasis on designing a coherent mystery up front avoids a troublesome reliance on GM improvisation -- something common in other games with mystery aesthetics but both unduly burdensome on the GM and rarely conducive to creating a coherent investigation experience for players.
As for Eureka's versatility, I think the description here actually undersells it. While Eureka is not going to be the right tool for the job for a story that isn't about investigation, I don't think its setting is really constrained at all beyond that. You could absolutely run a campaign set well before 1850 in Eureka, and you could run a campaign set in the far future -- the only real limitation there is that you'd need to replace a number of the tables you roll on for random encounters and adjust the items and weapons that investigators can own to fit the setting. At Eureka's core is a really good system for investigation and mystery-solving, and that system as designed is surprisingly versatile. If the core of a module is investigation and it's set in something resembling the real world, adapting it to Eureka is likely to work!
I enjoy a lot of the rules for monster PCs and the way having them kept a secret from other players is encouraged, but it's worth noting that Eureka as designed is not confined to fantasy and works perfectly well for completely mundane mysteries. The "investigative" part of the title is the core.