"I came across several discrepancies between what we were promised and what we were signing," he said. "I send each of the incorrect documents back."

Tim Dawson of Florida, an owner at Marriott's Summit Watch in Park City, said Marriott sold him a second week there with a promise that it would allow him to book his exact stays 13 months in advance, instead of 12 — giving him a better shot than most owners for the exact time he sought within his season.

"But then I found out that you can't book that month ahead unless you have two weeks of the same value that are consecutive," he said. "They didn't tell me that. The whole point of buying that second week was so that I could book in advance."

Juan Bosco Marti-Iturbide of Mexico even sued Marriott after he said it changed the availability of his weeks. He said in court documents that he spent $90,880 in 1999 to purchase annual Christmas and New Year weeks at Marriott's MountainSide in Park City.

His suit claimed he was told in 2005 that he would no longer be able to use the resort for two consecutive weeks during the holiday season. He sued seeking a refund of his purchase price.

Don Collier, a Westgate owner, said he bought a timeshare in Park City that officially sleeps six. After sales presentations, he expected he could make exchanges within Westgate's own resort system for other units that also sleep six. But that didn't work when he tried to exchange for a Westgate unit in Orlando, Fla.

"We found out that our unit in Park City, called a one-bedroom grand that could officially sleep six, was worth a one-bedroom Westgate unit in Florida. ... These only sleep four. We had four kids and a baby," he said.

So he had to buy a membership in a company that arranges exchanges between timeshare firms for about $130, and then pay an exchange fee for about that much again to obtain an acceptable two-bedroom unit in Orlando from another timeshare development (while giving up his week in Park City in the trade).

He said, "I would not buy a timeshare again. There are just too many good, cheaper alternatives."

LaRee Miller, a Westgate owner from Salt Lake, noted she was told by salesmen that "if we did not use our week, we could rent it out at a huge price. We have not had any luck doing that. We are not allowed to rent it out during the holidays as Westgate uses the holidays for a money-making business for themselves."

Sonja Clarke, a Marriott MountainSide owner, like many owners, said management companies will help rent her timeshare, but it keeps half the money. She said this helps defray her costs for weeks she cannot use but does not cover all of them.