We discovered really quickly that it was indeed important to have the cream at a little cooler than room temperature because the butter just would not come while it was really cold. My friend, Clair, had read the instructions more closely and had warmed her cream in the microwave and her butter came really quickly. So, I warmed mine up a tad and it worked like a charm! We used a spoon and our fingers to wash the butter and I think using fingers got more of the buttermilk out. I added salt to mine, folding it in really well on a plate and pouring off the extra water as it came out. This really helped a lot.
Now, I don't know if it was because my cream was really aged, but my butter had a wonderful flavor - nothing like the store-bought stuff. You should give it a try. I spread this butter on a slice of homemade bread and there's nothing like it in the world!