How much faster in wire VS wireless?

Wired

You should be able to get near your stated connection speed.

So if you are connected at 1Gbps, 950Mbps should be attainable

Keep in mind that this does not account for other bottlenecks in your system. (Such as HD, etc.) Or cable issues.

WiFi

The general rule of thumb is 1/2 your stated connection speed (for error correction) and minus some for encryption.

So if you were on 802.11N connected at 150Mbps and running WPA2, 65 to 70 Mbps should be attainable.

Keep in mind that this does not account for interference or your system's ability to encrypt data.

You have to tell us what you are trying to do..

Wire is much faster at copying files to the TC.. although it is hard to give you exact numbers.. since a large number of very small files will copy slower than a single huge file.. due to the time it takes to write details on the disk file allocation table.

There is a bunch of testing here for previous model .. http://www.anandtech.com/show/4577/airport-extreme-5th-gen-and-time-capsule-4th- gen-review-faster-wifi-/7

For internet of course there should be no difference at all.. wireless is still faster than internet which is the (in engineering terms) rate determining step.