Like the others, we've been HGVC members for a long time (10+ years) and have stayed at our home resort on a home resort week reservation all of once. To date we've never had a problem getting a reservation anywhere else in the system with the possible exception of Oahu.
The one caveat might be that booking one specific style unit for one specific week could be a little iffy at certain resorts, especially if you're not booking at the moment inventory is released for club reservations. Oahu I know can be difficult. I'd assume the ski weeks in Park City and Breckenridge might be more difficult as well. But overall if you're not locked into one specific unit type or one specific week, Orlando and Vegas are pretty easy most of the time.
FWIW our typical usage these last few years has been to book a 4 night stay at Elera in a Grand Plus one bedroom. I find I need to book 8 or 9 months out ensure I get what I want for the dates I want, which are pretty specific. I've also booked a 2 bedroom penthouse suite at the LV Strip location with no issues and we have an upcoming reservation for the Big Island. At the time of booking the reservation for the Big Island, I pretty much had my choice of unit style and resort at the 9 month mark with the exception of some of the highest cost units at each resort.
For us the reality is we have very little problems booking what we want but, we are advance planners and typically book at the 9 month window. Our needs are rarely so specific that we can't find something that's acceptable and usually find and exact match for our preferences. I have no desire to "upgrade" our ownership to Elera, even though it's become our preferred resort in Vegas. It's been easy enough to book and, if that ever changes, we're just as happy locked into our owned unit at the LV Strip location.
Your mileage may vary.
