We had 3 weeks timeshare in Australia (now changed to points). I have an exchange next year for a 6 berth narrowboat out of Barton Turns for 3 weeks from June 21 2008 - cost A$660 (about 250 pounds) per week . On top of that we pay around A$176 per year for our membership.
We usually have an overseas holiday every 2nd year on average. I am a mad keen skier, so a lot of our holidays are to ski resorts in high season. The cost is generally around A$400 per week. The great majority of the exchanges are at least 2 bedrooms usually with a couch wich also makes up into another double bed, usually 2 bathrooms & full kitchen.
We did a tour of Wales in 2004 (+1 is a member of a Welsh Ladies Choir), and rounded it out with a week on the Isle of Wight, followed by a week on a narrowboat out of Sawley Marina & then a week in Austria at Bad Gastein.
We have had timeshare for just on 25 years for which we paid around A$6000 per week & they were all floating weeks (RCI white). We also use RCI bonus weeks occasionally which can be very good value. When we owned weeks, we would quite often bank one year's weeks to extend our options. You can usually bank up to 2 years in advance which allows you to have 4 weeks available at once (one from last year, one from this year, & one each from the next 2 years). Points work similarly, but you are not limited to a number of weeks - as long as you have sufficient points, you can exchange - unused points expire after I think 3 years with our club (Interchange), and we still have access to RCI resorts as well.