Riverside is a neat community. However no realtor should advise you on appreciation. No builder should advise you on appreciation. If we or anyone knew exactly what would happen we would be billionaires controlling the stock market. Governments change, loan requirements change, money to lend changes, economy changes, client requirements change. None of us can predict this.
Otherwise you have a great location, a great elementary school. Easy access to DART. Shops and restaurants not too far away, not a lot of other places to build more new homes. Close to DFW airport.
As others have said, always always always use a realtor when you buy. Even a new home. We'll often same you time, money, and headaches. The builders reps should be nice and friendly, but you always want someone in your corner representing your interests. The sales reps are working for the builder.
To check out some of the houses in Riverside visit this link:
You might also want to checkout resales in La Villita. You can probably cut a much better deal there than with the new homes in Riverside.