You could definitely give
Play a try. It's still in Alpha stage, but should prove to be a good alternative for playing FLAC files natively and gaplessly on a Mac.
If it's worth anything, I would not convert FLAC files to Apple Lossless at this point. One of the biggest advantages of FLAC is that, when using proper encoder arguments, it will make sure the output files match the input files, so there is no risk of bad encoding. There have been numerous reports that Apple Lossless files can sometimes be truncated, etc.
You could easily convert your FLACs to Apple Lossless or just about anything else with
Max while keeping all the metadata intact, but keep in mind that gapless playback in iTunes can still be hit and miss. If you transcode FLAC to LAME MP3, no problem. However, transcoding FLAC to AAC will NOT result in gapless playback in iTunes. I haven't tested FLAC-to-Apple Lossless for gapless playback in iTunes, but if you're interested in making this kind of conversion, I would test some files for proper playback before deleting your original FLAC files.