Multiple purpose USB ports: The router's USB ports can be used for a variety of functions. They can host external hard drives, cellular modems, or printers. When a hard drive is connected, you can share the data stored on it with local clients or remote clients over the Internet, and you can even setup sync function, native Time Machine backup support, and PC-less download function. You can do basically everything you can imagine with the router's built-in network storage feature, making it a great NAS server.
VPN support and many other advance settings: The router comes with a built-in VPN server feature that allows you to create a secure virtual private network for remote users.
On top of that it also supports Dynamic DNS, IPv6, a customizable firewall and many other features commonly found in other home routers. There's one minor caveat: while you can easily assign a fixed IP address to a connected client, once the IP is assigned, the client is now remembered by its MAC address, instead of its name. Since the MAC address is a string of numbers and letters, this makes it very hard to know which client has which IP address when you have multiple clients on the IP reservation list.
Other than that, the RT-AC87U has new Adaptive QoS (quality of service) and AiProtection features, which are not available on previous models.
Adaptive QoS prioritizes the Internet bandwidth according to the type of traffic: Web Surfing, Gaming, Video and Audio Streaming, VoIP/Instant Messaging, File Transferring, and Others. You can easily use the mouse to arrange these categories in the list of highest and lowest priority and the router will take care of the rest. On top of that, there's also a function called "apps analysis" that allows for real-time monitoring of the Internet activity of any connected client as well as the total download and upload bandwidth being used. This is a very helpful tool if you want to find out which client or application is abusing the Internet connection. What I like most about the Adaptive QoS is the fact you can still manually program QoS rules if you want to using the Traditional mode. The only drawback is the fact that the router takes about five minutes to turn Adaptive QoS on or off.
AiProtection is a new, unique security feature powered by Trend Micro, and designed to protect the entire home network against viruses and malware from the Internet. And if a client has already been infected, this feature will also stop it from sending personal information. AiProtection actually worked well in my trial, even though it's hard to say if it can protect your home network completely. What was clear to me was the fact that if you turn the protection on all the way, certain settings/features of the router that are prone to security risks, such as port-forwarding, UPnP, remote access etc., might stop working, too.
All in all, this new Asus has the most complete feature set I've seen for a home router.
Since there are virtually no 4x4 802.11ac clients on the market, I used another RT-AC87U unit in bridge mode for testing, and the router excelled with a sustained speed at close range of 1,030Mbps, the fastest I've seen before. When I increased the distance to 100 feet (30 meters), it registered 381Mbps -- still very impressive.
When used with regular 3x3 Wi-Fi clients the router also did very well, scoring 504Mbps and 279Mbps for close range and long range, respectively. These were about the average among AC1900 routers on the market.
Note that 802.11ac only works on the 5GHz frequency band. On the 2.4GHz, the RT-AC87U also did very well with 171Mbps for close range and 56Mbps for long range.
What I like the most about the new router is its Wi-Fi coverage, exhibiting the longest effective range I've seen, some 300 feet (91 meters). Effective range is the distance at which a client can connect to the Wi-Fi network and remain connected with a stable connection.
The router also passed my 48-hour stress test with no problems at all. During this time, it was set to transfer data constantly between multiple devices, both wired and wireless, and of different Wi-Fi standards, and none of the clients disconnected even once.
Note that I tested the router at CNET's offices, where there are plenty of walls and many Wi-Fi devices, including those from adjacent buildings, that are out of my control. Generally, walls shorten the reach of a Wi-Fi signal, and other Wi-Fi devices create interference. As with all Wi-Fi routers, your results may vary depending on where you live.
When coupled with a portable drive, the RT-AC87U also did well as a small NAS server. Via a Gigabit connection, it scored 27MBps for writing and 32MBps for reading. These weren't as fast as some other routers on the market, even slower than those of the RT-AC68U, but fast enough for most casual needs for data sharing, media streaming and even Time Machine backup.
Overall, with the latest firmware, the RT-AC87U worked well in my testing. The router did become rather warm after working for an hour or so, but not hot enough to be of concern. Still, as with any other router, it's recommended that you place it in an open area.
The Asus AC2400 RT-AC87U Dual-band Wireless Gigabit Router is an excellent networking device with a premium price. In the end, it boils down to whether or not you can afford it.
If you can, you'll enjoy its excellent Wi-Fi range, unique feature set, and, if you're using 802.11ac clients, its great speed. Considering the fact that there are fewer 802.11ac devices than 802.11n devices, however, it might take a few years before you'll need something like the RT-AC87U.
That said, if you're already using an 802.11ac router, there's no need to upgrade just yet. But buying it now means you're doing so to future-proof your home for a few years to come, when you'll (presumably) have more compatible devices.