I'll keep this brief. I really like Overlord. Excellent story that both fulfills a desire to feel a bit villainous, rational, but sometimes "good" through our main Character. For a "transported to another world" premise, the cliches are for the most part avoided and the issues related are dealt with in reasonable, rationable ways. I don't mind an overpowered MC every once and awhile, and this novel does seem to provide the views of plenty of the poor underpowered saps.

Anyway,
Pros:
Story is great. Really hits a good itch that I love to scratch, with fantasy, magic, crazy powerful characters, battles of wits and technique for strong vs strong characters, and no moments of "bravery saves the day" here. If the strength difference is large enough battles are quick.
Art is fine. Honestly wish there was more, for a reason you'll see in the cons.
Great complex setting.
Overall quite captivating

Cons:
Pacing can be quite awkward. Definitely moments where a scene is so boring and predictable where I skip ahead a paragraph or two. Not too often at all though.
Characters. I can only take so many arrogant characters. Most are great, but jeez, the moment ANY character has the upper hand, it's boasting time (even if it's just the narrator boasting). Leads to a LOT of redundant and repetitive sentences.
Finally, physical description. I don't mind leaving things to the imagination, but far too often is a character's description left like too little or straight up missing. Yeah, there are a lot of characters and places, but sometimes I don't want to feel like the story is a dream I had where chunks of visual data just don't exist.

That's all!