We did a B2B the first cruise was 10 days to PNG and the 2nd was 7 days along the QLD coast but due to bad weather we went south overnight Sydney and the Newcastle and Tangalooma.
Embarkation was quite drawn out mainly because of staggard check in but also because of the demographics of the cruise. On the 2nd leg embarkation was a breeze with little to no lines. On the first leg the baggage drop off line was approx 200 pax long.
The demographics of the two cruises was markedly different. On the first leg were mainly more mature passengers whilst on the 2nd leg was the standard family crowd. This made an interesting contrast as a substantial number on the 1st cruise were what I refer to the Princess crowd, who had difficulty adjusting to the P&O routine especially with regards to booking/confirming your dinner time in the MDR. We had no issues as we knew the routine, but many evenings I noticed a large crowd in front of the MDR to book their next evening meal. The routine is that once you have booked on the first night they will pencil you in for the following evening at the same time, but not necessarily the same table.
A roomy outside quad cabin everything worked fine, no noise issues and ample storage space.