I don't know why, but I've really grown to like Gingaman over the years since it aired. I thought the villains were a creative mix, I liked the idea of the Seijuu, and I liked the heroes, even if they could have been a tad more diverse. And then there's the awesome Toshihiko Sahashi music.
I didn't realize it at the time, but when rewatching some Gingaman recently, I noticed how it tried to be fairly retro. From the "man" in their name, to the illustrated eyecatches, to hauling Masato Shimon out of retirement for the themes to the villains' voice actors...I wonder if there was a reason for that.