I've never used them and would not. Home Depot does use subcontractors and some are great and some are not. So, which one will you get? Besides, the subs are not getting paid as well as they could if they did the job themselves. So therefore, they will do a better job if you hire them directly - and it would be less expensive.
Besides, did you ever try to call your contact at HD? You have to know their hours, department, extension, etc. before you can even get the them. Then if you do, you also have to rely on their memory (will they remember you, your project, your contractor - do they have an sure fire way to contact the contractor without added time going by). I believe many people use HD as a price point, then go to an in-town store or installer to get the job done right.
JMO.
L