Features -
In the current market motherboard (and indeed almost all component) performance is very close. The days of a large performance advantage between boards using the same chipset are long gone. That is unless someone makes a HUGE mistake (like runs traces completely wrong). Now, the thing that differentiates different products is the features. These are things like power management, extra slots, better audio CODECs etc. It is these items that R&D teams work so hard to drop into what are really identical pieces of hardware at their most basic level. Asus has been working to drench their boards in features as a way to differentiate their products from others in the same performance envelope. That is not to say they are not still trying to squeeze every drop of performance they can out of the chipsets they use, but just that they want something else to give value.

Excellent –
WiFiGO!
BIOS Flashback
Direct BIOS
AISuite
DLNA media server
Thunderbolt
Intel LAN

These features make the Z87-Expert stand out from other boards in the same price point and in some cases at higher price points. BIOS Flashback and Direct are probably the two that most stand out to us here, but just as important are the Intel based LAN port for its compatibility and speed as well as the Thunderbolt connector.

In the middle (sort of good) -
SLI
PCIe Gen 3.0
High-end trace layout
USB Charger+
USB Boost
FanXpert

Here we have a group of features that add more to the mix even though they are items that you expect from a mid-range to high-end motherboard.

Floor Mats -
8-Channel Audio
USB 3.0

Not much to say about these items. They are not really features anymore, but an expected part of any motherboard.
You can check out the whole product page on Asus' website