Webdiver is such a cool anime. Yes, it has clunky PS1-era CGI mecha and early digipaint, but it more than makes up for that with cool mecha designs (the main robot turns into a train, and have you ever wanted to see an old-fashioned bomber jet, a steampunk airship, and a pirate ship as transforming mecha? Now you can) and a good story that doesn't assume the kids watching it are stupid. It has no fanservice, which is nice, and the show's other designs are pretty cool -- there's a cute little companion droid character (aside from the mecha), a massive mecha control room, and a neat mecha launching tunnel with countdown screens along the pillars. Its songs slap, and given that you hear them pretty much every episode during the transformation sequence, that's not a bad thing. It has interesting storylines that get into things like Goethian philosophy, time travel, false realities, alternate selves, and physics concepts. It alters the monster of the week formula quite a bit, providing lots of cool twists throughout the overall arc of the show and different, varied storylines in each episode. It uses the "rosy vision of the future" trope found in anime like Astro Boy 2003 and Gear Fighter Dendoh, a trope I personally love, but it can get dark at times as well and incorporates some Lovecraftian elements similar to Digimon. This anime is also a close cousin to Transformers, much like the Brave series and Shinkalion, because it's based on a transforming robot toyline made by Takara as an alternative to Transformers.
Beware, the subs are messed up for part of this anime, so it can be difficult to watch at times, but it's still incredibly enjoyable. I had no idea an early-2000s, CGI-heavy, digitally-animated mecha anime made to advertise a short-lived toyline would become one of my favourite anime of all time, but here we are.