Here is a short and somewhat vague review of Isekai no Seikishi Monogatari.
Edit: Time to make it less vague. Isekai no Seikishi Monogatari is a spin-off from the Tenchi Muyo (which I have never actually seen). As you can guess it's a harem series, but it focuses more on the comedy than harem part.
Story and plot were unimpressive, yet the the whole thing was still quite fun for the first 6 episodes. Things started to look dull and generic around episode 7. My real complain about first half was lack of story development. The story was mostly in the second half, and unfortunately it ended up being cheesy. I didn't like the inconclusive ending, it is one of those things that make me dislike harems. All that aside this series did benefit from the 45 min length of episodes. Had they tried to squeeze the series into 26 min ones it would be definitely worse.
The animation was generally good, but the CGI was only so-so (there were large quantities of that in the 8th episode).
There was a number of good BGMs, but only a few of those were memorable.
Kenshi was pretty awesome (he could rival Hayate in being skilled at everything), Most of the girls who were chasing after him had only a vague idea of how awesome he is (only Aura seamed to notice). He wasn't as much an idiot as others implied he is, but he had his moments (they mostly involved those crystal things). For some reason I liked Yukine, but I guess I generally like the "quiet girl" character type (just have a look at my favorite character list). On the other hand I dislike characters like Mexiah and Flora (both of them are nymphs). I also didn't like how Chihaha and Lashara treated Kenshi like someone inferior and use him for profit all the time. Call me whatever you want, but I wanted to see a Yukine x Kenshi x Aura ending or at least a "marry them all" one... Of course that did not happen. What we got instead was Kenshi running away from his harem, which by the end of the anime included nearly every female that appeared in the series (a few hundreds girls, which is a bit too much even for a "marry them all" solution).
The overall score is only 6, though I would give the first 6 episodes a 7. This series reminded me of Zero no Tsukaima, except it seemed written and directed better and the characters were more likable.