Honestly have never been too impressed with the AirPort Extreme or the Time Capsule. This being said, the improvements being described here sound like they are long overdue.
The new antenna design for the AP Extreme are great to have available for sure, while the bugs plaguing the Time Capsule in the past appears to be missing from the above article. Perhaps due to it largely being seen as a firmware issue? Now resolved, with the speed improvements to the Time Capsule, Apple users can once again backup in style.
Speaking for myself, I tend to trust using both localized and remote backups together, instead of relying on only one solution instead. Call me parnoid, but I would rather keep my wife’s Mac data safe as possible.