It depends what it is. I find big solid lumps of meat, like whole chickens, so bothersome to defrost that I don't buy them. Meat is quite a good insulator.

Small pieces, or mince, I can defrost in 10 minutes. I give it 3 minutes at the lowest power setting, then break it up, rearrange it and maybe remove any pieces that look like they are starting to cook. It's relatively easy to be sure there are no ice crystals left.