Not many people consider the Power Supply Unit to be an important part of the computer. All of them are wrong. It is a crucial part of the computer.
Do a quick search for 300 watt PSUs, and you’ll turn up with a thousand offers for junky power supplies for about five buck a pop. You’ll even find some for FREE + shipping. Wow! What a bargain, right? It’s 300 watts, right? That’s what’s recommended, “300 watts,” right? Wrong. Whether it is a 300, 400, 500, 600, or whatever size watt PSU you are considering, you need to get one from a manufacturer that has proven itself capable of designing an adequate power supply. The reason is, wattage alone doesn’t tell you anything you really need to know. A single PSU provides several kinds of electricity such as 5volt, 12 volt, 3.3 volt, etc. all at different amperages. All sorts of different combinations of these can add up to 300 or 400, whatever. The final line is that you need to have a power supply from a manufacturer who knows the “right” combinations, and makes hardware that consistently delivers power.
Ultra is a moderately new company when it comes to power supplies. They first made a name for themselves with their revolutionary modular “X-Connect” series of PSU’s. Their first efforts admittedly needed work, but Ultra admirably kept trying, and today makes some of the very best power supplies available.