AAC vs. Apple Lossless

Ok who can tell me the difference (quality wise and size wise) between AAC and Apple Lossless....I currently have Itunes set to import as AAC but I'm not sure which would better?>???

Apple Lossless is 10 times the size as AAC, but there is no loss in sound quality when ripping from CDs or when re-encoding songs from another format.

There is no "better" when it comes to audio formats because everything is subjective. If you can hear a serious difference between 128kbps and Apple Lossless, then it's probably 'better' to choose lossless for the higher sound quality. But, if you're like most people and can't hear the difference between encoders/bitrates, then go with 128-160kbps AAC or 192kbps/variable MP3.