Good but not without issues.

I used this app to convert a large collection (600+) of FLAC files to Apple Lossless. It worked, but I ran into the same issue that R Mongler reported where it would crap out after several hundred files. I eventually got it to work by doing smaller batches at a time, which wasn’t that big of a deal, but the small annoyance of not being able to drag and drop my entire project into the app and have it work while I make a sandwich or something kept me from rating 5 stars. If your projects are smaller or you’re willing to manage smaller batches, this app seems to be a good solution for converting flac to Apple Lossless.

BGnATC about FLACTunes FLAC Converter