I have been very happy with it. The build quality is very good. It seems like they used quality parts. When I tried to find a matching towel rack, I found out it costs $200. All the fixtures are high end Kohler product and costs bucks! Actually they have the same fixtures showcased very nicely at Irvine Lowes. I put in a door between master bedroom and master bath and found out that a doorknob is also high end and costs almost $100. I was generally surprised that they did not use cheapest thing available like most builders do.
Also, the customer service/warranty has been outstanding. They have an online form I fill out and I filled out a lot of service request, mostly small things and many I could have not bothered with. For all of them, the response time was very good and everything has been taken care of to my satisfaction. When I mention the service/warranty to my coworkers who have bought a new house before, they are very surprised at the level of service. For example, the builder inspected the roof on my house shortly after the move and replace some cracked roof tiles. When I asked how did they see the cracked tiles, the builder said they didn't see the cracked tiles, but they hire an independent contractor to check for cracked tiles for all houses after close of escrow.
For the road noise, I am at the far end away from Sand Canyon, so I don't have issues. It may be different for others who are close to Sand Canyon.
My wife and I toured San Marino, and we both liked the plan of our house better, mostly because of the loft in Sonoma 3 house we own.
Overall, we are very happy with the house. If the house had a nice view, it would have been perfect, but I digress...