A long time ago I fed London Natural Balance Potato & Duck Small Bites and was really unhappy with it. The smaller pieces were great, but the duck formula is incredibly hard (I had a difficult time safely breaking it with my teeth!). I then switched to Natural Balance Sweet Potato & Venison and although it didn't come in small bites, it was so much easier to break apart and London could eat the kibble just fine. She did great on it for a while (or so I thought), but it turned out that she wasn't getting enough nutrition from it and her coat began to dull. She also had to eat more of the food because there is less nutrition in it.
I switched her (and by this point we had Preston) to Orijen 6 Fresh Fish and within 2 weeks I could tell how much more vibrant her personality was, and after a month or two I saw how much healthier her coat was. I will never go back to Natural Balance, but a lot of members here feed it. It's a great food if your dog is allergic to a lot of foods, but if not, they are really missing out on nutrition in my opinion. I will be trying out Acana Pacifica next as it is slightly more moderate in protein whereas the Orijen is very high in protein, but the difference in NB vs Orijen/Acana or other brands is huge, I think.