In my experience, kip McGrath and kumon tend to end up putting extra pressure on kids as they end up with more homework from the tutoring - so essentially have anther curriculum they have to do. 1:1 tutoring on the other hand means that they are doing specifically what your child needs and (ideally) linking with the teacher at school to make sure they are helping the child practice the things that they are doing in class - rather than 'extra' stuff, its practising in the areas they need.

If you want 1:1 a but cheaper you could speak with one of the universities. Mostly they can offer students to do some tutoring at a lower cost... Maybe a teaching student could be another option to consider??