I grew up right as they were moving on from Bionicle to hero factory, so I’m a little biased towards HF. That being said, after seeing some bionicles, they seemed really cool and way better than the crappy reboot.
Damn, you brought me back. HF had more durable sets, but Bionicle had cooler sets and better stories. They were the Lego ultrabuild version of Playstation vs. Xbox, Android vs. iPhone at the time. You had to pledge your loyalty to one and were unable to enjoy both.