Down under w/Oneworld
 

Hi, I'm considering flying from UK to Australia on Oneworld award ticket in Business which basically leaves me with 3 options:
1) All the way on Qantas
2) All the way on Cathay
3) Fly BA to HKG and Cathay from HKG to Australia (slightly more mileage)

I would prefer 3rd option as from what is available only BA have lie-flat bed, and that is longest segment. on the other hand flying Qantas all the way is cheaper and you have luxiry staying on the same aircraft.

What would you choose?

AX

All 3 offer a lie-flat bed in J, but only BA has a horizontal bed (QF and CX have a tilt of a few degrees, somewhere between 7 and 9 degrees from horizontal). The QF bed is considerably wider and softer and generally more comfortable (both as a bed and as a seat), but some do not like the slope. So it isn't a simple choice, all 3 airlines have some advantages over the other. You just have to decide how their features fit into your preferences. I would pick QF in J and CX in F as being the most comfortable.

Care to share your personal specs? (age, ht., wt.)

BA flies to Australia

I find BA to HKG and QF from there, great. That would be my choice.

I would go with option 2. BA's J seat may slightly be better than CX's, but CX's service and catering beats both BA and QF.