I have a super duper picky dog so I feel your pain. I did use BalanceIt for a while & I was crazy nervous that Yoshi wouldn't eat it after investing so much time in planning and preparing the recipes. Hopefully I can help regarding the palatability...
BalanceIt is a fine white powder. It doesn't have much of a smell. There's definitely not a liver and/or seaweed smell like most other supplements. So it won't overpower the taste of the actual food...which is my issue with other supplements that I've purchased. It almost smells sweet. But it's a very faint sweetness.
I noticed that when added to food, it can give the food a somewhat grainy texture. That bothered me a little. I tried pureeing the veggies with the BalanceIt & a little chicken stock in my Cuisinart mini prep. That helped a little. But it ended up being too much trouble for 3 dogs with 3 different recipes.
I'm now feeding raw. Not because I'm a big raw supporter...but honestly, it's the only thing Yoshi will eat on a consistent basis. He won't even eat pre-made frozen raw consistently. He only likes "real" raw (PMR) that I make with the 80/10/10 meat/bone/organ ratio. My other dogs will eat whatever I feed them. Yoshi's the problem child. He got bored with BalanceIt after about a week.
Maybe I didn't offer enough variety in the meals? The recipes are a little boring to me.
Anyway...I would say that out of all of the complete meal supplements out there (and I've tried them ALL), BalanceIt is by far the best for the picky eaters.
I'm not sure how you feel about raw, some people just won't go that way. Trust me, I wouldn't be feeding it if I didn't have to. But raw might be something you could consider. If you're open to it.
Good luck with the BalanceIt!