I have a couple weeks at HGVC Vegas and have been a fan as well.
I now also am finishing up a purchase at Summer Bay Desert Club, which is turning into a new RCI Gold Crown Resort after some refurbishments and a land swap deal brought on by Harrah's who wanted the property of the former location.
This morning I watched a one bedroom week for SBDC go on ebay for $228 plus $500 in closing & transfer costs. A one bedroom resale for one of the HGVC's go for at least $4000 out the door.
I'd argue that the HGVC system offers more flexibility and options than Summer Bay D.C. will, but comparing apples to apples, 1 bdrm weeks HGVC vs. Summer Bay, I think there is a strong arguement to be made that the HGVC unit isn't worth a price 5 times that of Summer Bay if looking to use and stay in Vegas.
In case anyone is wondering, I've been using my HGVC weeks for stays in other locations and will be using the Summer Bay week for stays IN Vegas for an annual convention I attend.