The arena fighter show(the one pictured here) is fun, in a "turn your brain off, watch the bad CGI robots fight" kinda way. It's pretty much a model showcase that attempts to have a plot. The models themselves also have their own independent plot and plot arcs, told through the boxes and tie-in materials.

Chaotic Century is a more plot-focused Zoids series, though it can be a bit edgy at times, while still riding the "power of friendship" plot through the Organoids and what they can do. I'd honestly recommend giving it a shot if you want something with a little more depth, but don't exactly go in expecting an ocean. There's still a couple episodes of "our main character is literally stuck and useless to pad time, but once he's free, THERE'S GONNA BE A NEW MODEL TO BUY!"