Post revisions the salary ranges of the B4 are pretty equivalent.

NQ 6.4 - 6.8
1PQE 7.4 - 7.8
2 PQE 8.4 - 8.8
3 PQE 9.8 - 10.4

WP is highest based on monthly take home (as they made a point to do so) but is not necessarily the highest after factoring in bonuses.