The walk from Daily Garage 2 to the main terminal isn't all that bad. I'm giving away my secret here but I've always been able to find a spot on level 4, in the outdoor section (I have an older car so I don't mind the sun or snow beating down) right near the elevator and stairway. From there, it's only a 5-7 minute walk to the ticket counters or security.

On the other hand, I refuse to pay $9 a day to use the economy parking lots when I can park for free a few miles east at the municipal Herndon-Monroe garage (overnight parking there is permitted, unlike Metro lots) and then take the 5A bus or a $10 cab ride to the airport. The cab ride is faster than many of the economy parking bus rides, and for stays of 3 days or more it's cheaper. If I time it right, even the 5A bus from Herndon-Monroe is faster than the airport parking buses.

But for my business trips, I've found Daily Garage 2 to be pretty convenient. For leisure trips (non-reimbursable) I take the cheapskate route and use Herndon-Monroe.