I work right in the heart of Oak Hill, and as a child I grew up right outside Oak Hill. I'm a forth generation Austinite and can answer just about anything you need to know about the area.
Austin, for years, has grown North and West. Recently, growth has begun to the South and East. (Oak Hill is far South Austin/Travis County.) It is a beautiful area, but I am biased.
I wouldn't want to live anywhere else. If you have specific questions, please let me know. (I may be a lurker on this site, but I am willing to help out any Texan or potential Texan!)