I really like seeing dancers I "know" in both the "seen them before and can readily ID them" sense and the "have met them" sense.
For example, it was a delight to watch Polyana Ribiero rise through the ranks at Boston Ballet. Now that I am in DC, it is possible to watch Washington Ballet this way.
Similarly, as I have gotten to know the young people at the place where I take adult classes better, it has become much more interesting and enjoyable to watch them perform. In fact, I find that watching them more sharpens my sense of their strengths and weaknesses.
Of course, it is also nice to be in a place where a very wide variety of top-notch companies can be seen, though I do sometimes feel a bit "lost" when looking at the names in the program.
It would be hard to choose between seeing a performance by a new, unfamiliar company and an additional performance by a familiar one.