It is difficult to determine the quality of a pair of tin snips just by looking at them, however, there are some signs to look out for:
A high quality pair of tin snips should always be made of drop forged steel to ensure that they have greater strength when cutting.
The quality will also depend on the heat treating process of the steel. The steel blades of a tin snip should be hardened and tempered to increase the strength and durability of the metal.
A tin snip’s blades edges should also be razor sharp in order to shear through a piece of sheet metal effectively.
Information such as whether or not your tin snips have been hardened and sharpened properly should be in the product spec.
It is advisable to pay more and purchase a pair of high quality tin snips, than to attempt a cutting task with a poor quality pair.