Save your money! For the most part, I gave up mileage runs over a year ago. The only run I would make now would be if I were really close to the next status level and could easily make it with a single roundtrip for maybe $200.

First, miles are not as valuable as they were a few years ago. Devaluation is very real as airlines raise award levels and tighten capacity controls. That means for a mileage run to make sense it must cost LESS than it used to for the same number of miles or you have to get hold of a great bonus opportunity. In my view, airfares have increased, in some cases significantly, over the past year and good bonus opportunities are fewer. Therefore, from a mileage perspective, mileage runs are not the deal they once were.

Second, the allure and benefits of status have declined substantially. Here is my list of why status is much less important:
1. Upgrade prices have risen on many airlines. More $$ out of my pocket if I want to take advantage of that status.
2. First Class service is a shadow of what it used to be. Less offered for same/higher "cost" than before.
3. More RJs, less first class seats. More time in coach. Status doesn't matter there.
4. Electronic check-in kiosks and on-line check-in mean in almost all cases I do not have to wait in a line anymore. Status used to be great here, but now it doesn't matter.

The only real benefits to status now, as I see it, are the mileage bonuses and the priority you receive during irregular operations. In my view, those simply do not warrant spending lots of dollars for mileage runs.