I went from brand name to the Costco "Kirkland" baby formula.
I had no problems with it, same ingredients. My son also had no problems with the switch.. my Pediatrician said it's fine too.
For me I switched due to cost, and budget. As many perhaps do. I'm a SAHM, so any way to reasonably/safely/healthily save $$ is a help.
All formulas, will have a different appearance.. go by the ingredients. ALSO you want to make sure the formula has in it: 1) iron 2) DHA's in it (this helps with brain development/vision development etc. THIS is what my Pediatrician says is very important. If there is no iron in the formula, babies can get anemia. And DHA's are very important in baby/child and even adult development and overall health.
Good luck,
~Susan