For complicated due to the depths of rules, I think Dark Heresay is likely the winner. However, I think they work. As in depth and detailed as they are, they work for me.
For overall complication, SLA Industries wins the prize from me. The setting is all over the place between the different books over the decades of publication and companies publishing it. The magic rules are something that have never made sense to me and the combat is over the top. And I still love it and all of its supplements. The more that gets published, the more it all conceals.
And if that's enough of a reason to like it, well, I suggest you check out The Esoterrorists from Pelgrane Press. All of the monsters from SLA Industries could fit into an Esoterrorists game, because the Ocean Game is by the same creator as SLA Industries.