I'm not sure if timeshare is really an investment. From what i know is more like a waste of money, but every one decides what to do with his money. I found an article with the opposite side of this one:
http://www.timesharescam.com/blog/65-timeshare-travel-vs-travel-agency/
a black list of timeshare fraud resort, You should give it a read!! it's also pretty informative