I was faced with this choice too. I bought points at Aulani. It's easy to find nice places to stay at DL off properly and being a local I'm ok with that. Also Aulani points are cheaper than VGC points (direct) if that helps any. In the end as a local I couldn't justify the high cost of purchasing VGC.
Buy somewhere you want to vacation and you can 'el cheap it. Have a sister who bought a 'throw-away' at a place she doesn't mind vacationing every year. She can't trade it, rent it - she's tried = Nada, so she just uses it every year.