I've heard almost uniformly terrible things about the Lafayette principal and uniformly wonderful things about the Mann and Janney principals. The Hyde principal is also well regarded, or so I hear, but this is based on one or two parents.
Principals not mentioned above means I haven't spoken with any parents from those schools about their principals.
I don't believe any of these schools have to follow the DCPS curriculum. There are 9 schools making up the DC cubed (District of Columbia Collaborate for Change). I think this gives them some additional flexibility. Mann discusses is briefly on their site (
http://www.horacemanndc.org/). Per wikipedia (I know...I know...) "'D.C. Collaborative for Change,' or DC3, a joint effort of some of the District’s highest- and lowest-performing schools that have been granted autonomy as a tool for innovating with curriculum and professional development."