I'd never heard of it but I gave their website a look.
I selected a sample recipe for a healthy pet and for an arthritic pet. I think it is a good sign that it did not allow me to proceed with modeling a recipe for a health condition without veterinary involvement.
The development of the recipes being done by board certified veterinary nutritionists at UC-Davis indicates to me that it should be a trustworthy source of information.
There are other premixes, too. Alnutrin, U-stew. It really is a nice easy way to balance a home-cooked diet. I think more cat owners tend to use the premixes---dog owners seem to go for prey model mostly.
Check any premix for AAFCO or NRC mentions. Many claim all sorts of goodness yet are incomplete unless they are only listing the stuff consumers want to see. I'd say unless the ingredients include chemical names such as zinc proteinate and such they aren't going to be balanced. Most don't publish the mineral and vitamin numbers at all. TrainingJunkie, you would definitely be asking about vitamin D! I've just checked the min/vit I use for my dogs and there is plenty of D included - sigh of relief. I'd trust BalanceIT for sure but haven't used it.
WARNING - has added Baking Soda ingredient. Baking Soda can cause GI BLEEDING and other serious side effects.
I spoke with the company owner /veterinarian - Dr. Delaney many years ago. The supplements use baking soda. I asked the amount of baking soda my cat would receive for a recipe I generated. I told him the amount he stated is the equivalent of the amount for people on the baking soda box under medicine instructions. The box warns not to take the amount beyond 2 weeks for antacid use. He said he disagreed with the doctor that wrote the instructions for the box. I asked him if he could make the product without baking soda and he said no. The box also warns to use about 60% less if over the age of 60. I asked a supervisor at Iams if their vitamin mixes use baking soda also and they said no.
Later, I remember a pet owner comment from a website 'Dog Food Advisor' in 2016 that said their dog's stools were blackish and runny from the supplement. Black stool indicates bleeding. Baking soda has side effects -google 'Mayo Clinic, sodium bicarbonate oral route' warns it can worsen kidney and liver disease, intestinal and rectal BLEEDING, high BP, heart disease edema, problems with urination... Medical news today lists: headache, nausea, vomiting, thirst... Brain swelling side effect in people with diabetic ketoacidosis.
My cat had IBD and I was concerned about GI bleeding from baking soda. I use baking soda to clean and it took the enamel off my stove top and refrigerator. Also, I tried it as a shampoo and my hair strands would break off.