Apple's new Time Capsule is basically the new true dual-band Airport Extreme Base Station with a hard drive permanently attached to it.
Coming in a great design, the new Time Capsule's good looks can't make up for its lackluster set of features, unfortunately.
A lot of networking functions, such as Web filtering, DDNS, and Wi-Fi-protected setup, commonly found on many other routers, are missing. With the Time Capsule, you won't have very good control of which band--2.4GHz or 5GHz--you want the router to work in, either.
Its wireless performance was also a mixed bag. In our testing, the device had great 5GHz performance. Its 2.4GHz performance, on the other hand, could use some improvement.
The built-in hard drive of the Time Capsule is a very simple network storage solution, the sole function of which is to store files and share them with others; there are no other features, such as iTunes or Media servers. Its network storage performance was also lower than our expectations.
The Time Capsule could still make a nice device, even with all these shortcomings, if it didn't cost too much. At $500 (for the 1TB version--the 500GB version costs $300), I found it to be painfully expensive. For this much cash, you can find many alternative solutions that offer more storage and many more features.
You can read the full review of the Apple Time Capsule at CNET Reviews.