If you care about grain and lossless audio, buy the disc or download the REMUX. If you care about fitting 200 movies on a 2TB hard drive, x264 is your best friend.
However, be wary of low-bitrate x264 encodes (under 5 Mbps for 1080p). Those turn the beautiful Blu-ray source into a blocky, macroblocked mess. The codec is a tool; the skill of the person setting the switches matters more than the label on the file.