Review of High School DxD
Judge a work by how well it achieves what it set out to achieve. This show does not stand with the grates like Gurren Lagann or FMAB etc. However it is unfair to compare this show to those, because it wasn't trying to be one of those shows. Without this outlook I'd give this a 4. Highschool DXD is trying to be an in-your-face fan service/comedy show and it excels at this, in fact I'd say it is one of the best of its kind. The characters are flat but they don't need depth, that's not why you should watch this show, you watch this show tosee oppai on hot depictions of humans. So, taking that all into account, I say this show is a 10/10 compared to other similar shows. If you like ecchi/fan service in any way, this is a must watch.
On a technical level though this show is a 2: Better than hentai animation but worse than everything else. Also the sound effects are awful.