Despite there being an Anime adaptation of this franchise currently airing, it seemed like a good idea to check out the light novel version while waiting for that to finish. Both because I was impatient and because the Anime is based on the manga version (the web novel, light novel, and manga versions each have their own quirks).
Transferring over from the end of the Anime‘s 36th episode into the 6th and 7th novels, event-wise at least, is a fairly smooth experience. The main things of note are a difference in translation sensibilities (‘magic-born’ instead of ‘majin’ for instance), a much greater focus on RPG-like elements, and some minor character differences (e.g. Raphael being male, Rimuru’s personality trending more toward smarmy than carefree).
The 8th & 9th books on the other hand stand out both for being a heavily food-centric two-parter and for introducing the series’ worst concept so far: Tempest’s Labyrinth. Just unimaginably stupid; this isn’t Danmachi. And, worst of all, Book 10 devotes its first hundred pages or so to more completely extraneous Labyrinth bullshit. I sincerely hope that the Anime completely cuts out everything related (if it ever gets that far).
As for the 11th novel, there’s thankfully not really much to complain about here aside from the stage having being set for potential harem shenanigans later.
Ultimately when all is said and done, while the LN version isn’t objectively bad, it’s notably worse than the Anime version to the point that I would strongly suggest sticking to that unless you really like the franchise or don’t mind reading something that ends up intermittently annoying.