This has been an interesting post to follow and I've decided to stop lurking and put in my two cents.

I've done three mileage runs so far and they've been good in 2 ways:

During double mileage or other promos, I can get alot of miles for cheap that will get me somewhere interesting for less than I would normally pay without the mileage award.

Also, I like going somewhere for just a weekend. It's fun and flying is definitely not a "hassle" for me.

Flyer Talk is a good site. I've really liked the Mileage Run and Trip Report sections the best. Thanks everybody for all the information and reports!