I think weeks average about $20k for every year 2 bdrms, although premium views like oceanfront sell up to $30-40k. The maintenance fee for the weeks I own are $607 and $614 annually, although most beach resorts are now approaching $1,000. The bonus week is received from II for turning in a week that they have high demand for. These are not guaranteed, but depend on II. I have received one for my Williamsburg week for the last 3 years. If you have flexibility they are very useful. I traded one this year for a 160 point OKW week for a fee of $249. If you can travel within 60 days you can take any week in II inventory, otherwise it is very restrictive on what you can trade for.
Getaway weeks are OK, but limited to high supply areas in off season. You can also buy them through condo direct for $100 more than the II member price. I would not place a high value on this.
50,000 points seems light, but I do not think Marriott is offering very good sales incentives right now. They were much better when we purchased after 9/11.
The way I would think of it is as follows:
Purchase price - 11,940
Less Incentive of 50,000 x .01 = $500
Total Invested = $11,440
at 5% interest this equals $572 per year
Maintenance fees + 2 years interest = $2,178 per week.
This is equal to $311 per night tax included which equals a rental price of about $275 a night plus tax.
You can rent most of the mainland Marriotts for less than this and you also have to add exchange fees, etc.
You can probably rent Maui for that much in the off season. If you want peak season only it will probably be cheaper to buy than renting from Marriott.
By comparison, using the same formula my Marriott weeks cost about $120 per night tax included.
As someone mentioned the program is not as flexible as Disney. It is designed to be used 7 nights at a time and that is it.
We have been extremely pleased with our purchases. Good luck with your decision. HTH