When you're looking at recipes, specifically at cake recipes, accuracy is always stressed with the measurements (at least if it's a good recipe).
The problem with getting recipes from all different places, is that a "cup" is slightly different in different countries. A cup can range from 180ml to 280ml! So if you're making a large cake that calls for 10 cups of different ingredients, you could be 1000ml off just because you're not using the right cups.
So remember; try to determine WHERE the recipe came from, and then find out what they think a "cup" is. This will help you avoid troubleshooting a recipe gone wrong. I highly recommend keeping a conversion chart handy as well. The one I'm linking to is a more "middle of the road" cup, and where to go from there. I have one of these, and I love it.
Happy Cake Making!