It's pretty cool for a "harem" (though i don't really consider it one, given how consistent Yamada is with expressing his affection for Shiraishi). Series reaches something of a natural conclusion around chapter 90, and i had serious doubts about what author will do with the remaining 160+ issues, but she managed all right. It definitely loses some of it's steam after that point, as well as there are some slumps here and there (i didn't particularly appreciate pairing the spares in the epilogue and some other, pace-related issues near the end), but despite that it remained consistently entertaining and mildly captivating - i don't remember there being any major inconsistencies within witches lore and story (aborted arcs and characters put on a bus are different matter) - "mystery" parts have been rather good in their execution.
Nice, charming, irrelevantly uneven, and at times moving lecture.
edit: Oh yeah, insecure "harem lovers" obsessed with "polyamory" endings, stay away. It's not for you, so stop muddying the waters with your bitching.