This is where the disagreements begin. According to Neil Cooper, chief executive of the Timeshare Council, the trade association which represents the "respectable" end of the industry and seeks to promote "ethical" practices, there are two benefits:
"The first is that the standard of accommodation and fixtures and fittings is high - for many people better than they have at home or would get on a self- catering holiday.
"The second is that timeshare is a form of security that can be exchanged in up to 4,000 other resorts involved in exchange systems worldwide. If you have a week in a lodge in Scotland, you can swap it for a week in a condominium in Florida knowing that what you're going to is comparable."
So "security" means peace of mind, playing it safe? "Yes," he says. "You pay your pounds 5,000 or whatever and know you've got holidays in perpetuity. It's the opposite tack from the package tour, where there's an element of risk - you don't know what you're letting yourself in for - and where, I suspect, far more people end up disappointed.
"Timeshare's main problem has never been the quality of the product but the way it's been marketed, the way people have been cajoled into signing on the dotted line," he insists.
This is why legislation introducing cooling-off periods and other curbs to high-pressure selling was introduced in the UK in 1992, in Portugal in 1993, by the Canarian regional government in Spain in 1995, and throughout the European Union at the end of April.
Its effectiveness has, however, been mixed. In some countries the safeguards have worked well, in others they have made little difference.
This contrast is particularly marked between Portugal and Spain, two of the bigger markets for Britons seeking timeshares. In Spain the authorities remain hesitant and divided about the kind of civil law needed to support the Canarian and EU provisions and less scrupulous operators simply ignore them. Portugal has reacted more decisively and complaints to its national tourist office in London are, as a result, down dramatically. Vendors are less aggressive now, a cooling-off period is mandatory after every sale and there are rules governing ownership and standards which help to guarantee the continued upkeep and desirability of a timeshare resort.
Legislation has not been enough to convince everyone, however, and timeshare still has vociferous opponents.
"We keep timeshare at arm's length," says Dick Schrader, managing director of French Property News, "and in my opinion, the longer the better. Annual maintenance costs can work out more for one week than if you rented a house for a week."
Arlette Adler, membership secretary of the London-based Federation of Overseas Property Developers, Agents and Consultants, believes the cachet lent to timeshare by new regulations and reputable companies amounts to "no more than another change of coat. What's underneath remains the same as ever".
She says: "We do not accept members who do timeshares because we have people who've been in the business of property abroad for years and have seen them cause little but grief. Sooner or later, because their developers have either been greedy or over-optimistic, and have had to mortgage land or sell on management in order to expand or build elsewhere, these schemes don't work."
Swaps can prove impossible to make, she says, particularly in high season, and without rights over land, buyers can find a night-club has been built next door to their property.
"This can happen," admits Neil Cooper, "but most resorts are self-contained and protected."
Among the 3,000 complaints the Timeshare Council gets each year from the UK's 300,000 timeshare owners, neither this nor the average annual maintenance fee of pounds 180 features significantly.
The future for timeshares may be as the budget option. James Lavigne is a partner of Lavigne & Lane, a Florida law firm. "Timeshares are still very strong in our state, with reputable companies like Disney and Marriott offering good value," he says. "But the real shift in the market is towards sole ownership of villas and timeshares are being bought by the people who can't afford them."