Is the 1540 V4 good for overpronation?

Yes. It is built as a stability shoe with a firm midsole and wide base to limit inward roll. Walkers with mild to moderate overpronation are its main audience.

How does it compare with the 1540 V3?

The V4 moves to the Fresh Foam X midsole and a knit upper, which softens the step slightly and improves breathability. The stability character and width range carry over.

Should I size up or down?

Most owners stay with their usual New Balance size. If you wear thick socks or have a high instep, the wide fit gives more room without going up a length.

Is it good for standing all day?

Many owners wear it for long shifts on hard floors and like the support. The firm ride suits people who want control more than soft cushioning.

It has a 4 mm heel-to-toe drop, which is lower than most walking shoes. That takes some getting used to if you are coming from a higher-drop shoe.

Can I use it for running?

It is a walking shoe, not a running trainer. The firm stability build works for walking and standing, but runners wanting a softer ride should look at running-specific models.