We have stayed at HGVC Seaworld, Tuscany (International Drive) and Parc Soleil. All are great properties with plenty of amenities and activities. Seaworld is the oldest of three but has been refurbished. We took advantage of three heavily discounted stays before buying into the Tuscany property (our fave of the the three) for a relatively small number of every-other-year points. We already have a Marriott timeshare so this was plenty for us. They offered us a huge number of bonus points as an incentive and for us the price was right. The nice thing about HGVC for us as Florida residents is that we are also able to book open Florida properties at one month out for a heavily discounted cash rate (studios at $60/night, 1BR at $80, etc.)
The other great thing is that HGVC seems to have great trading power within RCI. We were able to trade for a week at BLT (1BR) this July back in January. That was with less than three-quarters of our 2012 points and none of our bonus points, so we still have plenty for next year.
The sales pitch itself is pretty standard. Videos of happy vacationers, breakdown of how much you normally spend on vacations vs. HGVC, etc. They do want an answer that day for offers to be valid, so do your homework if you think you're at all interested. If you're not, no big deal, they don't get mad. They know that you may be back in the future and they don't want to alienate you.