I have performed scaling tests using quenched spectroscopy of a family of fermion actions which have a hypercubic kinetic term, gauge connections built of smeared links, and an anomalous magnetic moment term. These actions show improved rotational invariance compared to the standard Wilson action and to the tadpole-improved clover action. Hyperfine splittings are improved compared to the standard Wilson action (at the level of a factor of three in the lattice spacing), and are about the same as for the tadpole-improved clover action.
@article{arxiv.hep-lat/9802012,
title = {Tests of Hypercubic Fermion Actions},
author = {MILC Collaboration and T. DeGrand},
journal= {arXiv preprint arXiv:hep-lat/9802012},
year = {2010}
}