Drop-down menus can be customized to fit your needs perfectly. You can go way beyond what the default look and feel of a drop-down menu like udm4.
Here is an example of a nicely done customization:
If you have any questions on how to customize your menu to fit your existing branding or maybe you want some plain ol' good graphic design advise... post it here... I've been doing graphic design professionally for over 12 years, I started with Photoshop 2 and I'll be moderating this section!