Good cooking question — answering as the UphillTech team:
I suppose that depends on what you're defrosting it for . The microwave (on low power) is safe and quick. The downside is that you're using a microwave, which means there's a good chance you'll actually cook the outside slightly in the process, and you're killing enzymes that are normally part of the flavour. The lower the heat, the less the impact of this, but it's still a problem. If I'm preparing the meat for marinating, stir-fry, etc., something with a powerful or thick sauce, then I wouldn't worry about it, but if it's going onto a grill with just a little bit of seasoning, you might...
Full answer by Aaronut: https://cooking.stackexchange.com/a/1439 (CC BY-SA 2.5).
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