I tend to prefer a round point shovel for the best overall performance, but square blades work very well, and are better as long as you are digging mostly soft stuff. What really improves performance for any shovel, whether round or square, is to sharpen it (a nice chisel edge works best). This is a trick I learned on fire lines, and one that I have applied many times on archaeological digs. So modified, a shovel is very nearly a light axe.