Let me state for the record that I am not a fan of incestuous themes in anything. The only reason I kept watching once I realized what was going on is not because they were steps, but because the step sibling thing happened when all of the characters were 16/17 years of age or older except one and he didn't count.
Alright now that that's out the way...
I'm a fan of reverse harems. I enjoyed the brothers. They're personalities were well developed except for maybe Iori's, who I forgot existed.. The brothers were charming, humorous, and bishie from #1-12 (like I said borther 13 is a kid). They ranged in ages, careers, but they eldest weren't that far from each other which allowed for clashes.
The female character known mostly as Chi was a ditz. As well as the brothers were written she was not. What little development they had, she had none. I was hoping she'd get a slap, but it never happened. I really couldn't tell why any of the brothers aside from the teens would fall her. She had nothing to offer them. The most I could reason is that their mother was an absentee so having a female in the house just confused them completely.
I would watch this for the brothers. I truly enjoyed them and wouldn't mind seeing all them again as brothers minus the step-sister.