In April 2008 a Soyuz made an uncontrolled reentry due to failure of the service module to separate during the de-orbit sequence. The cosmonauts survived due to the inherent ballistic stability and fail-safety of the design:
http://www.spectrum.ieee.org/may08/6229

NASA has finally conceded that the safest place for the astronauts is on top of the launch stack, with abort rockets to escape a failing lower stage, and with no exposure to damage from falling debris. These factors plus the increased safety of ballistic reentry explain the return to capsules with the Constellation system.

Shuttle vs. Soyuz Reliability
http://forum.nasaspaceflight.com/index.php?topic=7954.0

Soyuz vs Shuttle
http://salul.wordpress.com/2008/09/25/soyuz-vs-shuttle/

The mainstream media once again lives up to its long history of mangling science stories.

The report cites 5 specific fatal aspects of the loss of Columbia: depressurization, extreme dynamic loads, separation of the crew from the vehicle, exposure to space, and ground impact. Implying that this really means inadequate restraint systems is a joke. No amount of safety hardware would permit surviving the breakup and uncontrolled re-entry of (pieces of) your spacecraft.

Due to NASA politics, the report omits a more accurate summary statement that the Shuttle is an inherently flawed and unsafe design when compared to ballistically stable capsules that can and do survive uncontrolled re-entry.

http://3.paulhamill.com