I also grew up on a farm and loved going to my grandparents because they had 'city milk'. I think it was more about the product being icy cold with no need to 'shake it up' before drinking, than a difference in taste.
Iceblossom, my DH makes yoghurt from half and half. We tried it using commercial yoghurt as a starter but no matter how 'natural' the commercial stuff is labelled, we had much much better results using a starter from the health food store. The starters came 3 packets to a box but we only needed one. You only need to add half a cup or so from the previous batch, for 2 liters or quarts of liquid. DH also lets it drain through a big coffee filter for 24 hours before using. It is super thick and rich!
I think I would be interested in trying to make butter.