A the top of this page is a link to
DVC point charts. That will give you an idea. It varies a lot, for an weeknight in a studio at OKW in January for 8 points to Christmas weekend night in a BWV Grand Villa (sleeps 12) for 158 points. The system is set up to maximize flexibility - plenty of people own 150 points and get their week (plus) in a studio and are happy. Others own over a thousand points.
The best use of points is at the DVC resorts. If an OKW studio is 8 points, using points to stay at POR might be 12 points for the night (not sure). You can do it, but most of us don't think its a "good value." The points required for non-DVC options can (and do) change from year to year (usually going up).
Likewise we don't tend to think cruising is a "good value" A lot of members choose to rent their points for $10 per, pay cash for the cruise, and end up either saving points or making a few hundred to $1000 dollars (or so). But its important to examine the situation. What sort of cash deal you can get, how many points your cruise costs, how much bother are you willing to go through for rental, etc....Plenty of people use their points to cruise under "have them, might as well use them in a way that makes us happy"
Hidden costs - not really. Dues on points of $4-5 a point per year - they go up every year - generally 3-5% (but CAN go up as much as 15%). Trading out has a fee (for instance, using your points to cruise).
There is one big warning - examine yourself and your situation carefully. DVC is expensive and doesn't cover food/park tickets, etc. Its a huge amount of disposible cash for most people's budgets. Make sure you can afford it - and the trips that you'll be "obligated" to take. It isn't good for long weekends, people who can't plan a few months ahead, people who are just as happy offsite or in a moderate, or people who really want to do a lot of timeshare trading (there are cheaper good trades). It isn't good for people who like bargains - your bargain comes up front - DVC members don't currently get to take advantage of the dining plan for instance. It isn't good for people who want a full service hotel - no conceirge, no daily maid service (you can pay extra), and the staff isn't as servile as they might be at a hotel instead of a timeshare.