2 Best features: It fits in the car cup holder and its insulation it great, it kept ice longer than other bottles that touted similar claims.  The finger loop is handy, but it is in the way when it isn't folded down. (I wish it had the carbiner loop like the other bottle).  The bottle is metal and loud, I put a large can coozie on it to muffle the metal clanking. The airhole flap gets stuck and sometimes the only way to drink is to loosen the lid.