The usual wisdom is if you are running a single application, it can complete tasks more quickly with a higher clock speed and fewer cores. But if you run multiple apps (a browser, Photoshop, InDesign, Illustrator, office apps, etc) all at once, go for more cores at a lower speed. In practice, you will rarely notice the differences in clock speed between 2.7 and 3.5 unless you're hammering your system.
Since most CC users are running more than one app at a time, I'd recommend the more cores option. Here's a good reference:
Do I need lots of cores or a faster CPU clock speed? Cores, processors, GHz, multi-threading & hyper-threading explained…