This mc is, no doubt about it, quite unusual. He's greedy to ridiculous levels. He doesn't want to give anything anything unless he earns something from hit. He'll stoop to any level to get what he wants. It's pretty good, but it'd be nice if he was a bit smarter(he's not really smart at all although he's not stupid either, I've yet to see a single instance in this manga where he did anything that could truly be called brilliant in terms of brainpower) and wasn't as greedy or selfish as he tends to be sometimes. I like his traits, but sometimes it's overdone. I also can't understand why he'd whine about things like adding an egg to cheap ramen, an adition of around 200 won, far less than even a single dollar. Surely he should realize that his body is first priority if he's going to use it to play and earn money, right? But he doesn't. Oh, and he can be pretty petty and violent for no reason. I personally dislike his attitude against his summoned beings that serve him.
Anyway. The first season had pretty crappy art, a bit too realistic and dramatic for my taste. The second season had much more preferable art, well, until the last several chaptesr where the drawer decided to say "f*ck it" and copy-paste screenshots of bad game graphics into the background, the type of crap you'd see a more than a dozen years ago, chunky and polygonal. It really stood out and made things less amazing.
As for the characters, I guess they're pretty good. Can't say I hate any of them, at the same time I can also say that I don't care much about them. They can be funny when they show up but contribute with little else. The comedy is so-so, sometimes hilarious enough for me to laugh out loud, sometimes enough for me to smile and sometimes just not hitting home, missing completely. The comedy and light-heartedness is essentially what makes this an interesting enough manga(and novel) to read.
Overall, it was pretty good, at least I didn't feel bored when reading through all 2100+ pages in half a day. The setting is pretty interesting and it somehow works despite some flaws here and there. It's not anything truly exceptional though. I've read over 20 volumes of the novel version before deciding that it was turning to garbage and I wanted to drop it because it gave more boredom than enjoyment. This is what happens with unnecessarily long novels, they lose steam and crash, a crash that never seems to stop as it gets worse and worse. The author could've paced this differently and finished it in 20 volumes, going for more wasn't a good decision. Too bad he didn't. I actually feel like the manga is superior in many ways because it's much faster to read and we can see everything happening quickly. The novel is full to the brim with exposition and useless information that we never wanted to or needed to know. Some of it is nice, like details about his crafting and thoughts which we don't get to see here, but much is just sheer garbage.
So, I recommend the manga, it's a good and light read. If you've read the novel and wonders where season 2 ends, you should know where if I mention "grass porridge" and "tomb/pyramid". It never got to any romance parts yet, I guess some of that might happen in the next season.