Re: rubber ducky
Some thoughts:
Dinghies are invaluable tools that greatly enhance the boating experience. Being able to easily travel from boat to shore is essential unless you only plan day sails around the local waters.
A 33 footer has plenty of room on the foredeck for a small inflatable. If you need something even smaller, you can get a nesting dinghy that doesn't take up much more room than a liferaft.
Liferafts are insurance. You buy them hoping you'll never need to use them. If you decide to buy one, get a small one, unless you intend to travel with a large crew. Reports from those who have used theirs say that having two people in a six or eight man liferaft is uncomfortable and dangerous, as the occupants get thrown around considerably in survival situations.
Dinghies do not make good liferafts. They do not typically self-inflate, are very difficult to board from the water, and are not generally provided with a canopy to protect you from the sun. Exposure is second only to drowning in cause of death for those adrift. Those who say "my dinghy is my liferaft" either don't sail offshore or haven't really thought about trying to launch and board a small boat in 20 ft seas and 50 knot winds.
If you don't actually believe you could have to spend several days to a week surviving in your life raft, then you don't need one. Invest in a good pair of inflatable life jackets instead, and equip them with rescue lasers and PLB's. You'll be talking about hundreds of dollars instead of thousands.
And finally, many world cruisers travel without liferafts. They're most useful in cases where you've struck something, the boat is sinking, and the conditions allow you to safely swim to the deployed raft. Even a liferaft is a crap shoot if you've been rolled in a storm and you're dealing with those aforementioned winds and seas. You don't just placidly sit in the raft and wait for the boat to sink from under you, after all. You have to deploy it, jump in the water, and swim to it. Some have reported that upon inflation, their raft promptly snapped its painter and blew away in high winds and seas.