Well, I first read the manga, then I went directly to the webnovels and read everything available, and I must admit, I was quite hyped. For those thinking on starting it, let this be said: MC is OP, and so are his servants, yup, if you are expecting him to struggle, that will be kinda rare.
Think about it like in DBZ, how can he get even stronger? Well, he gets stronger, can he get even stronger? Yup, is he the strongest? The strongest demons, dragons and the Hero are still stronger, well, all important characters get kinda broken skills anyway... Think Predator and Great Sage
are OP, pfff.
As expected of the isekai genre, there are a few RPG typical rules here: Power boosted Master also power boosts servants, at the beginning, it almost feels like Pokemon in regards to species evolution, yet even with such a powerful "possible military force", MC is quite the peaceful guy who helps everyone and wants to build a country to laze around.
Another fact of this world is that summoned people are not really rare, there are many of them around, unlike Rimuru who was killed and ended up reincarnating, these summoned ones are actually intentionally summoned, so they remain human and everyone has their own unique skills and more powerful bodies compared to normal people, if you know Log Horizon, compare "Adventures" with "People of the Land" levels of difference.
As many stories have, there are usually some key characters that change the hero into something more noble, and the one here is quite touching, both in a happy and sad way, something I find very rare for stories of the isekai genre
I also found it to have a very unique way in expressing the sense of loyalty from the servants: Some are grateful for being helped by him and wants to be useful back, some feels like they would be discarding their own honor in submitting themselves, just to soon feeling admired and honored to be under him, even the ones that feels like they could go crazy anytime soon and rebel end up with quite a natural admiration towards him.
And while this is more about the webnovel, there are some really fast battles, thanks to the OP level of the many characters, even fights that would seem to drag on end up getting insta-finished simply because the enemy wasn't aware of the newer upgrades of MC's Servants, which is nice both for not having useless dragging out filler and skipping overall irrelevant battles, the reactions of both enemies and friends are quite nice too, reminded me of Mr Satan on Cell Games when he wasn't trying to explain and was just confused at everything.
He is usually also well prepared for battles, so if he knows the enemy special abilities, he will not take the wrong servants with him, this avoids the typical "You activated my trap card" of the enemy and dragging the battle more, though that can't be said for non-Rimuru battles
Overall, at first I compared it with Overlord, which I read the manga up until the Lizardmen arc as of now, and in comparison, I significantly prefer Rimuru's way of "conquering", which is done with humility, mutual understanding and some paranoic levels of security when compared to Momonga/Ainz, who wouldn't mind a massacre to let one of his "children" to grow...
Also, Wisdom Lord Raphael best Waifu!