Optimal cutting is achieved with curved blades. Because then they can "dip into" the material that is being cut and pull it towards the point at which the maximum cutting force is applied.
Strength isn't the most important factor for fast and safe cutting. You will get the best results with rescue equipment - which, remember, is extremely heavy - that can orient itself to the optimal cutting angle and make the necessary cut without your needing to intervene. This is also facilitated by the curved blades.
To obtain the best possible results a cutter needs to have easy-to-use intelligent controls that allow the operator to use it intuitively and in any position without distorsion of the wrist. So, it is good to have a star grip control, that is user-friendly in any position. This is also ensured by the fact that the controls are separate from the handle.