Bushwood is posher, larger houses overlooking the Wanstead flats. Lower Leytonstone is considered not so nice but I can see that changing with Crossrail and the flats shooting up at Stratford. Leyton's getting better too.
This is what I was going to say as well, Bush Wood area is nice. There are some nice places on the other side of the A12 as well, I saw a place on Chelmsford Road which was nice and quiet but an easy walk from the tube/Red Lion etc.
Bushwood is posher, larger houses overlooking the Wanstead flats. Lower Leytonstone is considered not so nice but I can see that changing with Crossrail and the flats shooting up at Stratford. Leyton's getting better too.