Hawks or hand boards, whatever you call them (and there’s certainly a North/South divide on that debate), every plasterer needs one. They are simple in design and to the untrained eye they all look the same. Although there’s a set shape, the differences between manufacturers run a lot deeper than just the label.
Metal hawks can be more solid feeling in the hand than a plastic one but are a little heavier. Plastic hawks are lighter and although they may feel different to hold, they are less of a strain to hold all day. Older plasterers who may work infrequently may find a plastic hawk easier on the hand and wrist than a metal one. Plastic hawks are also a good investment for a novice plasterer or a DIYer, as they are cheaper than metal ones and the ridged surface helps hold the plaster on it even if it is held at a slight angle. Getting used to holding the hawk at the right angle can take practice, so a plastic one is great for learning and not wasting too much plaster as it slips off a metal one.
The other great factor in choosing a plastic hawk over a metal one is the cost. They are cheaper, so if they are lost or left behind on a job they can be easily and cheaply replaced, and are available from most DIY stores. For those with sensitive ears or a particular dislike for the sound of metal on metal then a plastic hawk also eliminates the scraping sound.
Metal hawks are longer lasting than a plastic one, however, and there are some with a ridged surface to help keep the plaster from slipping off, as well as flat ones for the experienced plasterer. Nela manufacture three sizes, giving you a choice of weight as well as surface area, and they also have concentric circular ridges, and they are a little cheaper than the Marshalltown alternative. All in all, it is a matter of personal choice, but there are advantages to both plastic and metal hawks, it just depends what you are looking for.