I hadn't said anything about this long but useful post by Jon Goff, primarily because I hadn't had the time to read it. I just glanced through it, and it's definitely worth a read for those interested in rocket theology.

One point that I didn't really see addressed is (to me) one of the biggest disadvantages of single stage--off-design performance. Because a single-stage vehicle will have a much larger dry mass/payload ratio on orbit, if one wants to take it to higher altitudes or inclinations, the payload penalty will be much more severe than that for an upper stage of a multiple-stage system. Altitudes can be dealt with by staging in space (i.e., a tug that meets the vehicle at low altitude and transfers the payload to a higher-altitude facility), but inclination hits can't be accommodated in this way.

But I remain a launch-vehicle agnostic. I'd like to see a lot of different concepts developed, and let the market sort out which is the best, rather than engineers arguing over napkin sketches, or with Powerpoint charts.

[Update a few minutes later]

I should note that the comments are worth reading too, including contributions from Antonio Elias, Gary Hudson, and Dan DeLong.