My experience with them has been mixed too.
I've concluded they are too focused on the profitability of a single transaction and not thinking about the value of a long-term relationship with a customer. They are quick blame me for the problem and slow to help resolve it. That might not be anyone else's experience, but it has been mine.
I've taken most my business elsewhere.
From a fast delivery standpoint I've found LMC truck generally gets stuff to me by the end of the week if I order at the beginning of the week. With ChevyDuty I'd work on my project on teh weekend, order more stuff Sunday night and it rarely arrived in time for the following weekend's use.
LMC if I order on Monday its here by Friday. That might be a clue where I've taken my business.