The DGL-4300 is an all-black router that's suitable for use either lying flat or in a vertical position, and small rubber feet are provided in the box to allow you to set up the DGL-4300 in this fashion. As routers go, the all-black style with blue indicators is a reasonably classy look, but at the end of the day, it's still a router, and routers aren't really fashion accessories. Being a mixed wired/wireless router, you've got the option to hide it away in a cupboard if it particularly interferes with your interior decor.
The DGL-4300 features what D-Link calls "Gamefuel", which is a fancy marketing term for some Quality of Service implementations that prioritise what the router identifies as gaming-related traffic. In theory, with the DGL-4300 in use you should get smoother gameplay experiences because the games traffic coming in and going out of your router has priority over other Internet applications such as Web browsing or file transfer. The DGL-4300 integrates the settings for popular games (and some P2P clients) directly into its firmware, so you don't even need to know the normal port settings -- you just select from the list (which will presumably be updated with future firmware updates), which at the time of writing stretched from Age Of Empires to Xbox Live.
On the wired side, the DGL-4300 features four Gigabit ethernet ports. These won't specifically increase your online gaming performance, but if you're into hosting local LAN contests it should ensure entirely lag-free contests. Wirelessly, it's an 802.11g standard router with D-Link's particular flavour of 108Mbps wireless connectivity which it labels as AirPlus XtremeG. If you've got XtremeG cards in your networked machines, it'll give you the increased throughput, otherwise it'll just work at 54Mbps. 802.11b is also supported, although if you're in the market for a specialised gaming router like the DGL-4300, you really should dump the aging 802.11b gear.