At first glance, they seem to do the same thing. Both allow you to handle ISO files, burn them to USBs, and manage disk images. However, looking under the hood reveals a classic "Scalpel vs. Swiss Army Knife" scenario.
It does many things reasonably well—mounting, converting, editing, burning. It is overkill for a simple Windows installer, but indispensable if you manage complex image archives. rufus vs poweriso
Rufus for writing speed. PowerISO for virtual loading speed. At first glance, they seem to do the same thing