Well, using it regularly, but I don't think I've put on as many miles, in total, as Kacie did last Saturday! 
Amazing.
Since I use it in the a.m., I'm good for about a half hour, and then I've got to shower, eat, and head to work. So my runs on it tend to be short - 2-3 miles (except for that 5-miler with the new Superfeet that nearly crippled me.). But it's getting used pretty regularly.
Yesterday, I rode my bike home in all daylight. Amazing the difference in the past few weeks (and the benefit of arriving at work early, so I could leave a bit early). Soon, I'll be able to add bricks to my bike commute days - ride home, grab the shoes and head out for 2-3, so my morning treadmill runs will become less frequent.
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle