A PC supply is made for running a PC. It puts out multiple voltages. Often they need a load on outputs that are not used on a printer. They do not have the ability to adjust the output and in some cases they do not actually meet their stated specs.
A single output industrial supply does only what you need it to do on a printer. It puts out lots and lots of +12 volts. For a printer you want a 30A supply. Just as with PC supplies, some industrial supplies do not meet their specs. If you are going to get one - get a name brand. The same thing is true on the PC supply. Once you get to name brands, the industrial supply is likely the cheaper option.
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Just as in your other thread on the same topic, the Alltronics motors will cost you more money and not produce as much torque when driven by the normal stepper drivers. Motors rated for good torque at < 1A are better for these printers than high current motors with the same torque ratings.
