Homework at Mann seems reasonable, and is not too time consuming. I think there may be some variation across teachers. one 2nd grade teacher that we don't have does have a negative reputation -- too much homework!
We've had a fantastic experience at Mann, particularly with one child who needed extra support in the classroom and overall to do well. The principal, Ms. Cole, has been incredibly supportive and the teachers we've had have ranged from good to fantastic. We feel very, very fortunate to have had our child in this school where everyone worked as hard as they possibly could to help. It's been wonderful to see how a strong teaching and support staff can make all the difference for a child' success.
Our "twice exceptional" child has done extremely well with the interventions and supports they've provided. I do think you need to advocate for your child to be assessed, but they will respond very effectively once issues are identified.
Despite its historical strong performance, within the past 5 years there has been a marked decline in both test scores and teacher morale. Much of this can be traced to the testing scandal that led to the departure of the prior principal, Mr. LeDeaux (and can be clearly seen when looking at the drop in test scores in 2012.) Adding to the relatively low socioeconomic diversity of the school (esp. for Oak Park), is the materialism of the students and their families. A lot better options elsewhere in OP.