Perhaps an 8 is overstating the value here, as this show nothing spectacular, but does a few things well. Something that I quite appreciate is the treatment of the characters. They start out seeming fairly archetypical, but some realistic portrayal keeps them from becoming two-dimensional. Furthermore, they avoid several cliches, such as the leading female falling for the leading male.
The producers could have made this a very dark show, but despite the circumstances, everything remains somewhat happy-go-lucky. Actually, my initial impression was that this was a shameless Evangelion clone. This similarity however, is only skin-deep. The monsters may be interchangeable, but the story-telling and tone are completely different, as are the mechanical designs and level of violence. Even for 1999 the design of Daiguard seems a little dated, but this along with the PG action creates a somewhat nostalgic experience.
All the characters a very likable, and have surprising realism. I feel it would have been very easy for each of them to stick to their archetypes, but they all have a little depth and development, except perhaps for Akagi. Maybe I just feel this way because I'm a car nerd, but I think that even Aoyama's blue Impreza was a likable character. Unlike Ibuki's book, it's never introduced, talked about, or even really focused on, but it's always there. They could have given Aoyama something non-descript, easy-to-draw, but they chose this specific model of car, and I feel that adds something to the depth of Aoyama's character.
---Minor Spoilers---
I think my favorite piece of this puzzle though, is the lesson that anyone can be your ally. Shirota and Saeki, who are both introduced as unbearable assholes, eventually become very likable. Shirota may have even become one of my all time favorite characters. Even Busujima, playing the villian up until the last minute, is mentioned as siding with Shirota in the end.
---End Spoilers---
Overall, Daiguard is a pleasant experience, if not a completely novel one. If you want a mech anime that's more about the people than the fighting, and that leaves you feeling warm inside, watch Daiguard.
