I find Max about the best - quick, simple, effective. I transcoded my entire library from FLAC to ALAC (rip with EAC on Windows, convert to ALAC for playback on the Mac) - loaded everything up in Max, set it to process 10 at a time (rest are queued) and left it for a few hours.
dBpoweramp is the way to go for sure. If you use the free version, be careful with the naming of your source (FLAC) files, since it doesn't give you the option to customize output file names. If your music archive is large enough, you will surely run into problems (as I once did after waiting about 30 hours or so for the conversion to complete) with this unless you use something like foobar2000 first to make a more complicated structure, based on the FLAC metadata, of the file names. The program will run the conversion without error (unless something really weird happens to you), and it will be up to you to check the number of source files vs. the number of output files. Chances are good if this is a large batch conversion that some output files will be missing unless you've made your file names very intricate, as dBpoweramp will overwrite files without prompting in the free version. My advice would be to set up foobar2000 to include at least artist, album, disc number and track number information when renaming your files prior to converting with dBpoweramp. You can always use iTunes afterwards to handle the file naming of the Apple Lossless files.
I highly recommend Max.
Free, open-source audio CD ripper and audio converter. Handles all the most popular codecs/formats, like Apple Lossless, FLAC, WavPack, MP3 (LAME), AAC, Ogg Vorbis and lots more.