Great series. The art is amazing (though the MC's eyes can sometimes look really wrong lol), and the various heroines are great - they're all stupid hot.
That being said, the characters are COMPLICATED. The MC is a good guy (initially, and he tries to be the entire time, with varying levels of success), but each of the girls has their own issues. Two of the girls are mother-daughter, and it's a classic case of trauma begetting trauma. There's a bit of 'revenge' thrown in there, breaking of the haughty, but ALL the characters grow in various ways. For all that sex is the vehicle by which the plot moves, there's a ton of drama and character growth.
And as for the ending... I'm... honestly not sure how i feel about it. The final chapter seems kinda rushed, but the plot itself had great pacing all the way through up until said final chapter. I feel like the final chapter should've been 3-4, and it would've been PERFECT length, but as it is it's only mildly truncated. I feel as if some important conversations were just handwaved away, but the way I see it is that the ending was absolutely viable... just skipped a few chapters.
And yes, it is a harem ending. Don't think too much about it, as I said, some obstacles were handwaved away, though at least they were clearly setup. AKA they weren't plot holes and deus ex machina, it's just that they were set up properly and then never shown.
I still rate this as a ten though, because up until said final chapter rush, it was some of the best i've read. Recommended.