When choosing armor, consider what you need to defend against or block. Matching sets will give you a lot of resistance in select areas. Mixing will vary your defense, but might not max out the defense in any given category. Most people build a few sets and switch it out depending on the situation.

Also, check to see if your armor or shield will provide any bonuses to match your play style. As a sword user, you'd benefit from the Wolver line and also the Bristling Buckler line.