RCI actually has two distinct pools of resorts -- Weeks, and Points.
DVC has access to some of both. Out of RCI's claimed 3,242 total resorts, DVC members have access to a little less than 600.
The RCI Weeks system is generally for a 7-night stay (although you don't have to stay the whole time). During peak seasons, checkins may be limited to Friday, Saturday, or Sunday at many resorts. DVC members may also have some access to RCI Nightly Stays, which are Points System resorts. And just to make things even more muddy, some resorts operate in both the weeks and points systems. As you can imagine, with 3,200 resorts (many of which are independently owned), there is an enormous variation in these policies...as there is in quality of the resorts.
DVC/RCI operates on what is called a "fixed grid" system, with fixed point costs varying only by season, as listed above by Doc. This grid has nothing to do with RCI Points -- it's a negotiated currency schedule between RCI and DVC. So if you stay in a 1 BR at an RCI Gold Crown resort in high season on one trip, and a one-star dump 1 BR also in high season -- you pay 160 points for each.
In
anyone's system, exchanging out through a company like RCI will
usually (but not always) mean something of a downgrade in accommodations. You will also
generally (but not always) be paying some points premium for the exchange...which is why some say exchanges are not a good use of your points.
Realistically, by far the best use of DVC points is for stays in a DVC resort. I would not ever recommend RCI exchanges except as a last resort. If you messed up and forgot to bank points and they are about to expire, then you have to option to deposit them into RCI as a last resort. That's the only situation where I would deposit DVC points (or my Wyndham points, for that matter) into RCI.
If I wanted to go places where DVC doesn't have resorts, I would buy a different timeshare, not consider DVC/RCI as a viable alternative.