I love the +damage on bio armor but, yea, it's got some holes that become very noticeable as you start increasing difficulty. Go take it for a spin in a max diff ITF and once the seafood buffet at the end of the first mission shows up, you'll see exactly what I mean. Can you plug the holes, yea, to a point, but in very similar ways to what you have to do with fire armor. But it's at a pretty heavy cost just like FA as well.
That said, yes, my mace/bio scrapper sits around the 1:30 mark for pylons which seems a bit on the excessive side.