Some interesting structural differences are not captured by 23andMe nor even with technology like Ion Torrent, for example repeat sequences related to ALS, Huntington's, etc. To get the full picture ultimately you'll need a full sequence with longer read lengths to span the structural variants, and you'll also want the methylation/epigenetic markers which convey which genes are turned on or turned off. Just knowing you have the gene doesn't mean nearly as much without knowing if it is turned on!