Finite-Element Sea-ice Ocean circulation Model (FESOM) uses unstructured triangular meshes and is employed either as standing-alone global ocean model or as part of FESOM-ECHAM5/6 coupled setup. Several examples pertaining to studies focused on polar oceans will be given to characterize the potential of FESOM and also to indicate typical difficulties related to the strongly variable resolution. Brief intercomparison of FESOM to a global cell-vertex finite-volume setup is presented. While it is more numerically efficient than the finite-element setup of FESOM, it requires special measures to maintain stable performance because of its too large velocity space. Most effective stabilization is provided by either computing the momentum advection on scalar (median-dual) control volumes, or making use of the vector-invariant form. Both approaches effectively trim the nonlinear term in the momentum equation to the size of scalar space.