I bought all my RTA cabinets through a kitchen remodeler that used these folks, but I found the designer used an over-the-sink cabinet that was far too small to be useful, so I ordered another from theCabinetSaver.com. Not only was the cabinet itself extremely affordable, but it shipped in only a couple days. It came packed very well, no damage whatsoever.
But here's the most impressive aspect: not being a professional cabinet installer, I screwed up and drilled a couple holes in the wrong place for installing the hardware on one of the doors.
I contacted the company and asked if I could buy another door, and Bill Z. wrote back "Sorry, we don't sell just doors so what I will do instead is just replace your door free of charge." Two days later and I found that Bill had sent me TWO replacement doors at no cost (likely in case I made the same boneheaded mistake, haha).
I'm so impressed with this company. Please consider them for your ready-to-assemble kitchen and bathroom cabinetry.