I am always looking for better quality ingredients. During Christmas, 2010, I decided to use the Amish Market fresh churned butter and was planning on a switch. At the time, it was $6.00/lb to LOL $4.00/lb. Plugra European butter in my area is $10.00/lb, so that was not an option at the time.
To test the butter, I used it in my personal holiday baking. My tried and true recipes slightly altered due to the high fat content. My brownie gems (in mini cupcake liners) had a pool of liquid butter on the bottom of the foil liner and some cookies were flatter. I immediately realized that if I chose to use this butter, all of my recipes would have to be adjusted for the additional fat and I felt it wasn't worth it.
I use local dairy products but the higher fat content is offset by a much thicker product. I have to shake the heavy cream to get it to start pouring. But I think the additional body (like changing out buttermilk for sour cream) was enough to offset the higher fat.
You just have to be careful with fat changes, lower or higher. It throws off the balance of the recipe. I have recently started mixing whole milk and heavy cream instead of buying half and half. It has changed one of my recipes. My yellow cake is now more delicious and helps the cake last a little longer. It's a butter based cake and for me, these tend to dry out faster. The higher fat seems to give me another day.
On the other hand, subbing a butter, sour cream, milk, cream cheese, or any dairy product with a lower fat product or one that is higher in liquid content will hurt the flavor and the structure. Dairy fat, to me, adds a fuller, deeper flavor. That's why for cheesecake, it is best to use a low fat recipe rather than just sub out the lower fat or off brand product. Cheaper dairy products seem to have more liquid and less fat. Another factor in dairy is ultra-pasteurization, which robs the milk, etc., of the rich taste and some thickness. That's why I use the local dairy products. They are pasteurized at the minimum by law and have much more flavor and body.
I looked for an explanation that will explain it better than I have. I studied the balances, but I use that knowledge to modify and create recipes. Here is what I found for you. It pretty much covers the needs of a baked good.
After several attempts, I cannot make the link work. CC has obviously blocked it. Just email me and I'll give the link.