They are not hit or miss. They only use the best. If you have a job done and are not happy you call and it will be fixed. They will check up on the complaint Lowe's has dropped contractors who do not work up to their standards. Each and every job is graded by the store. Store Managers want nothing but good feedback, each and every quarter every Lowe's is evaluated.
In my opinion, they are definitely hit and miss.
We haven't gotten our carpet installed yet but so far DH and I are pretty highly annoyed with the guy. The experience where he came to detail the house left us a little

and now...
He called us at 9:30 am yesterday (ugh, it's my Saturday off, can't I sleep in?

) and basically said we needed to pick a date then. We told him we couldn't, as one of us would need to take a day off of work, and we'd get back to him. It didn't help that we were half asleep and laying in bed. I mean, it was Valentine's Day.
Anyway, he said "Well, I might not be able to make it, I don't really set appointments, I just need a day you guys would be able to do it. How about February 26th? I should be good that day.."
I was like... Uh. We'll call you back.
I plan on calling him back and letting him know if I take a day off of work to be there, he better be there.
