Oh now that is a ridiculous comparison. I'm sorry, but i know how these magazines do things, ive written for them!
Comparing two power supplies of different brands immediately invalidates the entire process! im suprised that wasnt obvious.
The efficiency of any given power supply depends primarily on the switching frequency used. The Vregs on a motherboard can be upwards of 1 mhz, which is why they can supply such massive wattages to the CPU, and only need passive cooling. Most PSUs will use a freqency in the region of 50 khz, cheaper ones will be lower, and more powerful, more expensive psus will use a higher frequency.
Unless you know this frequency, you cant make any judgement about the efficiency of any power supply.
Also, the current draw matters even less when you consider that the current draw of any given system will be up and down like a whores drawers, according to CPU load and throttling, ditto for the GPU.
Anyway, the shuttle isnt that bad. The cooling is VERY efficient, even if it doesnt maintain very low temps. Heatpipe systems can handle huge wattages, and keep things adequately cool for a standard processor, and thats all you need.
No, they arent any louder than a typical system of the same spec. Obviously if you make an effort to quieten down a system, its going to be quieter than a shuttle, but you can quieten shuttles too! They use a fan that was designed primarily for long life, not airflow or noise levels. It just needs swapping for a good ball bearing fan, and the job is done! The cpu uses a standard 80mm fan, and its not a hard job at all.
I dont think its any harder to put together iether. You are saved the problem of putting the motherboard into the case, which causes the most problems for first time PC builders. Its just small and a little fiddly, but it DOES come with proper instructions, so anyone with a bit of sense and some dexterity could do it.
Upgrades arnt much of an issue. By the time you get to upgrade time with any PC, most of it is obselete, and you end up replacing almost the entire thing. Upgradability is only an issue when you upgrade every 6 months, rather than every 2 or 3 years.