Drink covered a lot of good points. To that, I'll add:
1. Mooring is convenient for getting going -- as long as you are okay with always starting at the same place, and having all your nearby destinations be the same ones.
2. When I moored in Victoria, it was about $750 in fuel to run to the north Island -- 2 days running, plus allow a weather day, There's $1500 and your first week of holidays accounted for.
3. I spent $8000 on a trailer, and between moorage costs and running costs, figured I paid it off in around 2.5 years. Now a run to Port McNeill is 8 hours or less, and less than $150 diesel in the truck. I go to the West Coast, which I would not without a trailer.
4. I never worry about my boat in a storm - I know where it is, and I can walk to it in 30 seconds.
5. I can traIler to the ramp in 15 minutes, which is less time than it took me to get from my moorage to the outside of Victoria harbour.
6. I only moor the boat when I want to fish several days a week from the same place.
Pros and cons for sure, but those are mine.