Maybe it's because I buy A LOT of ink but Nazdar has always been awesome with us. Now, my comments are specifically about the bulk ink in jugs. They stock all my stuff at the local branch(about an hour from us) and have put backstock on our floor. Only one issue with a bad batch was resolved at a huge expense to them and with them bending over backwards to get us back up.
Getting ready to put it on a HP9k and a 10K as well. I'm doing so b/c the chip issues with megaink (which we otherwise like a lot) have become too much to put up with. It's at the point that I have to order 2 of every cart I need just in case. Fellers hasn't been helpful that much (understandable), and has sent me to MEga directly. To be fair, Mega has done a lot to be accommodating but it's clear they have an issue to fix. When I take the cart apart, it either has a seiko chip in a HP cart or the wrong color chip in it, someone's not paying attention when loading these things.
With regards to overloading the chips (or underloading the bags) that's not a big deal at least for us, it's when the wrong ship is in there rendering the cart useless from the start. With the kind of margins (profit) that exist in ink, there's no excuse for poor service.