Have tried both in brushed and brushless motor indtastions. The shafts have always been plain SS running in brass tubes.
Prefer oil, the grease seems to solidify and drag, whilst the oil just slowly emulsifies with the slight water ingress.
Must add, always fit shaft oilers and oil prior to each days use. The shafts are removed and cleaned every season. Have never noted any wear bands.
Am interested in other opinions but oil (regular light engine grade) works best for me.