Depending on the quality of the tool (and the price you are prepared to pay), bolt cutters can have a number of additional features which increase their performance or longevity. At the other end of the spectrum, fixed-jaw compact cutters have very few additional features.
Recessed blades
On quality bolt cutters there may also be small recesses at the base of the blades, to hold in place pieces of metal being cut and stop them sliding up the blades, as they otherwise can do.
Two neck adjustment bolts
While some full-size bolt cutters may have only one adjustment bolt, better quality bolt cutters have them on either side of the jaws, enabling both blades to be moved. Although models with a second neck adjustment bolt are more expensive, they give the user more control over the position of the blades in relation to one another. This makes it easier to keep the jaws correctly balanced and better protects the blades from damage.
Some top-of-the-range bolt cutters have a ratchet hinge, where teeth wedge and hold the jaws closed at each stage of compression. Rather than needing to maintain continuous pressure, you can make the cut in a number of stages, taking a break each time to relax and summon strength before squeezing the handles once again.
Assisted return handles, where a heavy duty spring automatically reopens the handles when you loosen your grip, are very useful if you are doing repetitive work, such as snipping wire fencing.
A handle catch
On spring-loaded bolt cutters like those described above there is usually a catch at the end of the handles to hold them closed for storage.