I think Leviathan and Spinners are both not really all that good. The meta is moving away from high crit builds for a reason. And so if you stack either sets with Thief mundus your crit chance would be really high but your base damage would suffer. And if you used either set with Shadow mundus then you are nerfing yourself, cause TBS would give more crit chance, and more HP and also a side buff of extra of either mag or stam, depending on which of the types you are. The Thief full divines is stronger than Leviathan or Spinners.

I ran 5 Levi + 5 VO on stamblade for a while. Having that much crit from gear allowed me to use Shadow instead of Thief, but the missing weapon damage/max stam from other sets was noticeable. Overall, it was good, but not great. I still like it on StamSorc for solo'ing Craglorn dailies and such, as the constant crits lead to amazing survivability with Crit Surge up, but it's really only good for "playing around"...there are many better options for really trying to max your DPS in a group setting.