Both series feature a master-servant relationship between a guy and a girl in which the roles are somewhat inversed (the supposed servant acts sometimes like he is a master in a master-pet relationship). If you liked one of the series, you might find the other one enjoyable as well.
Both manga feature an odd mixture of shoujo and shounen. In both series the female lead is short and socially awkward, while the male lead is tall. What's more, in both series the male lead declares himself the girl's servant, but he isn't all that keen on following the girl's orders. Both manga seem like they would appeal to the same kind of audience, so if you liked one, you'll probably like the other one too.