Their system is that they have several types of cake and several types of fillings that you can mix and match. The cake options include apple and pear spice, cheesecake, espresso, banana, poppyseed, excellent chocolates and vanillas, and more. The filling options include a wide variety of chocolate mousses and truffle, mocha, hazelnut, custards, and fruit fillings. Between all the options, you could create exactly what you want.
We'll probably do some combo of decadent chocolate and a sweet, simple vanilla and fruit (they don't charge any extra to do different flavors on the different tiers!). The banana truffle was delicious, but I'm not sure it compliments our menu.
Design-wise, you know my distaste for fondant, both in taste and appearance. CAKE does amazing buttercream designs. Again, simple, but expertly executed. Ours will feature a clean, art deco-style dot pattern like on this cake: