I find the title bar a bit annoying when using the mouse in Internet Explorer. Many website have their navigation at the top, after all.
You can use ModernMix's setting (under Advanced) "Hide Windows 8.1 Update 1 fullscreen app titlebar".
Side effects to installing ModernMix:
By default, ModernMix makes some other tweaks related to running Metro apps in Desktop windows, which you can change in General
App previews in the Win + Tab sidebar seem worse (totally black, etc.)
Switching apps through Win + Tab doesn't have animations
ModernMix has a (free) 30-day evaluation trial and costs $5 for unlimited use.