As of 2014 Q2 we implemented test runner sessions in Telerik® JustCode™'s unit test runner.
For every test run started Telerik® JustCode™ provides a new result tab, thus a history is preserved for all test runs in the current VS session.
Now the comaprison between the different runs is an simple task. You can easily check the execution time and test's status differences at a glance.
The maximum number of test results can be set from Unit Testing Options window.