I heard my name being called...
I don't know much about the Stanley Martins. I have some friends who did own one of the Brambleton models, so I've been in one a few times, but I can't really speak to the builder experience. My friends' home was very nice, but they were only in it for not quite two years before a job transfer took them out of state.
I know a lot more about the Miller and Smiths - two of my friends/neighbors work for them and I have many friends who live in the Phase I townhouses and single-family homes. (I *love* the 1920s Collection, but my husband vetoed the detached garage, so we ended up in a Centex instead.) I will say that I really like the Rhapsody's kitchen/family room area - it really becomes the heart of the home in all of the Rhapsodies I've been in.
Most of my friends seem really happy with their homes, with a few minor problems - for example, many of them have already had to have all of their trim repainted after a few years. Also, a few of them have had birds getting into their garages through a gap in the eaves - nesting, leaving lots of poop and other damage. Otherwise, I haven't really heard any Miller & Smith "horror stories." If you're considering new construction with any builder, you just really need to stay on top of the process. Be sure to get a reliable, trustworthy home inspector to do a pre-drywall and pre-closing inspection.