I recently rewatched the series [just finished the last episode again, actually] and I guess it goes without saying that it has its good point and its bad points. The plethora of biblical references is interesting, and, unlike many of it's genre [the demons-must-be-stopped-by-an-elite-faction-of-the-church sort] it thoroughly involves the church to a much more realistic extent.
I was immediately interested by the dynamic between the Pope and his siblings and their character growth throughout the series.
That's something that I greatly appreciated about this anime, that you don't always see: character growth, and legitimate, realistic character growth at that.
Something that's instantaneously striking when you first so much as see a screencap of the show is the brilliantly gorgeous artstyle and attention to detail. Structures are ornate, shading realistic and dynamic, people of varying face-shapes and body-types. It's not one of those take-away-the-colors-and-you-could-assign-any-hair-to-any-face-to-make-a-different-character animes.
On a whole, the plot is wonderful, however it just sort of... ends. As far as conclusions go it felt unsatisfying. I completely understand the want to create the idea of "life goes on" and "even if the series is over the characters' lives aren't" I get that, absolutely, but it just fell a little flat. Not awfully flat, but a bit flat all the same.
Overall, I really enjoyed Trinity Blood and would recommend it to anyone interested. It's really not your typical vampire anime, and it's worth giving a try.