I have both on my car. If your budget allows for only one of these options, I would agree with the others here that the B&O system is something you will use and enjoy everyday. I ordered the seats because I like the ventilation feature in the hot summer months, but it is something I could live without. The massage feature is OK, but not as good another car that I have with this feature.
2013 650i GC, prev 2010 550GT