You do not write which class you will travel in. Either way the two above routings are IMO not the right choice. UA is consistently below average and sometime far below average in both business and economy - especially now when E+ is gone for *G. For the SYD - SFO leg I would go NZ (I know you have a milage problem - but NZ is the way to go in both C and Y - way beyond UA). PHL-LON is a bit more tricky - not a great airline choice - but alternatives are not straight forward (LH: PHL-FRA-LHR or SK: EWR/IAD-CPH-LHR or SQ: EWR-FRA LH: FRA-LHR).