I'm not going to lament over its harem based nature, views on women or anything like that because it's a "power fantasy" novel and that's really the main reason many would read something like this. If you have issues with anything like that then don't read this because it's gonna be constantly throwing that in your face non-stop.
So the start for this series is really strong compared to other similar works. A problem I find with others such as Martial World or Martial God Asura is that your kind of just thrown a generic main character with zero backstory initially and then they suddenly get thrown a huge amount of different powers all at the same time and it gets kind of difficult to keep track of it all which puts me off. ATG handles this a little better by keeping it relatively simple and feeding you it a little bit at a time and spacing out his aquisition of powers more. Don't get me wrong, he still gets a bunch of powers very quickly but it's done in a slightly more digestable way in my opinion.
Some SPOILERS from here on;
I was thoroughly enjoying the series up until a certain arc when he meets his step-brother and parents. If you're reading this series primarily for the harem based aspect then a certain elf girl is introduced here and while it never pretends that she will in anyway join the MC's harem and makes that very clear right from the get go, it still urks me because she's basically the only "attractive" female character that is with someone else other than MC. If she wasn't given much attention then it probably wouldn't be an issue.
However...they spend a disproportionate amount of time focusing on her and your step-brother (who's just a pathetic, soft hearted, boring vanilla guy) and it really made it hard to get through this part, not to mention the issues that are prevalent through what I'd call the main big 1st arc of the entire series are cranked up to 11 here with really long winded repetitive speeches lasting many chapters.
There's some great moments during this time too but it was kind of a struggle...but take heart that after this everything gets so much better and up until the current latest translated chapter as of me writing this (so chapter 1598) it's just been getting more and more awesome. The world gets more interesting, the long dragged out speeches are cut down, the situations the MC ends up in are all great and the women too make you forget all about elf girl because the scale gets that much grander.
In particular the current situation going on is probably the most interesting yet and it's painful having to wait every day just to read one more chapter.
Suffice to say the scale of the world and powers are huge and even though I usually hate timeskips, the way they handle the perception of time in the series actually makes me not care in the slightest. I'd say the only thing I find lacking is more descriptive sex scenes which for the most part range from heavy implications to only very vague details on what actually occured. I assume this is to keep its content rating down but I think it would be better for it if there was a little more spice in the mix.
I'm hoping that the series will continue on for several more thousand chapters at the very least and thankfully it does seem like certain things have been setup and shown that lead me to think this will be the case.