I've had both Interval and RCI memberships, and I like many features on Interval better, for example the hotel pricing is usually lower. They also give you the final price, unlike RCI that hides in the fine print the resort fees, or the fact that RCI plays games with their "Savings Dollars".

Interval also seems to have a bit higher quality properties. RCI may have more, but many are very questionable establishments.

The representatives on the phone seem to have more experience and are able to answer your questions truthfully, unlike the RCI reps who are always trying to sell you something.

I hope this helps you decide.

They've tied in with Westgate and i use westgte properties as exchanges with them. They are really helpful.