Canon 100mm f2.8 Macro or Sigma 150mm f2.8 Macro lens?

More than happy with my Sigma 150mm ( non-stablised ) lens.

Really sharp, easy to handle with a good tripod mount position.

I think with macro lenses, longer focal length makes for easier lighting.

Not convinced that f2.8 is too important for macro work, as depth of field is short at the best of times.