I used to own in San Joaquin Hills. Construction there started in 1998 and they are still lots available to build new houses. In my opinion, S&S is a good builder and the homes were pretty much trouble free. Just like any community, there are pluses and minuses to living there.
Pluses: new construction and no Mello Roos, the tax rate was only 1.02% if I remember correctly, HOA was about $160/month, guard gated, 2 pools, very convenient location (close to 5 and 73 freeways), walking distance to Moulton elementary, walking distance to Laguna Niguel regional park, close to all sorts of shopping, most houses have 3 car garages.
Minuses: no real sense of community (like Ladera), people generally kept to themselves, due to its location it gets hot there in the summer (in the 90s), unless you like chain restaraunts you need to drive to get some real food, the layouts of the older houses aren't very good (small kitchens and huge formal living rooms), mostly small lots (you will definitely pay a premium for a larger lot)
Not a bad place overall. You can get short sales or foreclosures there in the 600K range now. As far as demographics...I think it was pretty equal between asian, middle eastern and white.