Usually I use the other which uses oil, but yesterday I went to make a cake and found that I had bought butter recipe by mistake. Then I saw you could use margarine or butter. I didn't want to wait for the butter to get soft so I used a stick of margarine and it came out great. Actually it was the best cake I ever made but that was also because I baked it at 325 instead of 350 and was using 9 inch pans and they didn't fill much, so I just baked it for 25 minutes. I also used flower nails in the middle so they didn't dome on top and it was evenly baked.
I like to use the WASC type recipes for white and vanilla cake. I still haven't found a moist scratch one that I love. The cakeboss wasc is great. I use it with the BC French vanilla. It has melted butter, sour cream, and I add a ton of vanilla extract as well. Super yummy and moist. It also extends the cake batter by adding cake flour and sugar, and will fill 2 nine inch pans nicely.
......also used flower nails in the middle so they didn't dome on top and it was evenly baked.........
The use of flower nails in a 9" pan really is not necessary.
I have baked 1000s without any and still get a moist, hump free cake by baking at lower temps.
I prefere to use regular rather than butter recipe cakes. I don't use oil or butter in them either. To me using a butter recipe mix was just an added expense of the butter.
Now I do have to say my baking was done before the change in size/formula of the new mixes so I don't know how different thing will be now.