Regarding tipping, Princess automatically charges you $10 per person per day to cover all your tips, except room service and bar service (which has 15% added on automatically). You can have that auto-tip adjusted or eliminated by the purser's desk with no problem. I leave the auto-tip in place and tip additionally in cash to those people who I feel have earned it - often the room steward and my waiter if I'm on traditional dining or have established a relationship with one in Personal Choice and have used a specific one throughout the week.
I generally tip $2 for regular room service, up to $5 if I have a full dinner delivered and set up. These waiters aren't on the tip pool covered by the auto tip.
I like Princess' auto-tip system. It eliminates a lot of the angst new cruisers have over the last night tipping, and with so many dining venues, you don't have to worry who to tip, how much and when. I just give additional when I feel it's deserved, and everyone is happy.