Your dog is vomiting -- go back to the Hills Science since that worked for the dog before.

But if you are looking for recommendations, I give my toy poodle Merrick Classic Healthy Grains small breed (my vet recommends against grain-free dog food) and she does well on it.

We’ve never had a problem with Iams and add toppers like plain yogurt and pumpkin.

You can't just switch a dog's food suddenly. It has to be done gradually.

Feed your dog what they tolerate best. Ignore the ridiculous social media ads for food. We feed our lab purina pro plan and our vet has been happy with that (and the dogs coat is gorgeous - unlike when we first got him as a rescue).

"WSAVA compliant" is the standard, but the quality ranges from cheap purina/iams to crazy-expensive Royal Canin. You can look up their guidelines and find another brand to try: wsava.org

The vomiting occasionally thing may be non food related. If the dog is vomiting up food, that's one thing. If it's bile, could be a feeding schedule issue, or stress, or other things. Realistically, animals vomit sometimes. If it's not a daily issue but a once a month or so problem, it's probably nothing to worry about.

If your dog was doing well on Hill's, go back to it.

If not, ask your vet for help picking something WSAVA compliant

I switched my dog from Hills Science (for small dogs) to Sundays freeze dried dog food: fell for all the hype about human grade ingredients and not overcooking. Picked a brand randomly. Also wondered if all her dental issues were stemming from dog food. Anyway, all seems fine except the Sundays food does not come in small chunks. The dog seems to vomit occasionally and I am wondering if it has to do with the size of the chunks. Been breaking them up (which has helped) but seems a bit much to have to do this at each meal. Ready to switch again...any recs for another brand. I'm completely confused by all the brands/types.