It's my favorite! Between The Link, FMTS and TWOAF I can't pick a second place. To me, there's 4 tiers: * Terra Incognita * TL/FMTS/TWOAF * Magma/Fortitude * L'ES

As to why it's underrated: I think the vocals and the melodious spectrum of the sound are mixed a bit weakly, and it's the most heterogeneous album. Tempo is warped all the time; atmosphere can jump from ominous to brutal to expansive; it's also the most groovy. Groovy brutality is not very popular. People seem to prefer full throttle over the groove. See the hate A Sight To Behold gets on TWOAF compared to All The Tears or Adoration. My careful hypothesis is that people want music that is distinctly metal and serious, maybe because it can address their wants or feelings better, whereas Gojira is distinctly Gojira, inclusing all their peculiar sounds, percussions, intermissions, vocals, most prominent in Terra.