Cholula

yyzfler...and other interested parties....a "timeshare" is just as it implies. You are buying just an amount of time...say 1 week or whatever....to use at your home resort or to trade. You have no equity and in essence are renting the property.
The Marriott "shared ownership" concept differs in that, at least in Hawaii, if you buy 1 week, you are buying 1/52 of that unit with 51other people. You are not locked into a specific week but can choose from whatever weeks are available when you place your reservations.You own the physical property as well as the land it occupies. You get a deed and fill out all the reams of paperwork you would do in buying a freestanding home. This shared ownership property, if purchased in the right location, i.e. Hawaii for example, increases in value and is part of your estate forever or until sold.
Most traditional timeshares fall in value as you are usually locked into a specific time and you don't have an equity position.
This may be a somewhat simplistic comparison of timeshares versus shared ownership but you get the idea. Having said all this, the shared ownership is considerably more expensive to purchase than the pure timeshare as you are actually buying something physical. I think the greater cost of shared ownership scares some people away...but in real estate as in most areas, you get what you pay for....