My builder says he uses Delta and is going to give me a catalog from which to choose. Is there any quality difference between what he can get through a plumbing supply store and the big box stores?
Apparently yes. The stuff from the big box stores have some changes (and different model numbers) to keep the supplier costs lower. They may have cheaper parts, thinner gauge metal etc. But if the part numbers are exactly the same, it's the same stuff.
My plumber also wants me to buy from his supplier, which is alot more expensive. He says he won't warrant anything not purchased through them. I've noticed that the big box stores sell a Delta series 14 and his supplier sells series 17. I'm guessing the higher the number, the better the quality?
I think the 17 series has the thermostatic control?
I think I'll go ahead and use what our GC uses (for warranty purposes). If I want to change out the shower heads later, I might do that. I wish there was more of a choice (Delta) in the kind of kitchen faucet I want, though.
If it's a faucet then I would insist on getting what you want. If you have to pay the difference, or write some sort of warrantee exclusion for the faucet, so be it. You're you're the paying customer.
Get the faucet you want, most faucets are guaranteed for life by the manufacturer so parts are given to you. Labor is not included but parts are easily replaced and thus not to costly. Get what you want. Keep the paperwork so you know the model and date of purchase.