TeamCity server version is 2017.2.3 (build 51047)
NCrunch Console Tool v3.20.0.6 vs v3.17.0.2
2 main issues related to logging:
1) Log verbosity Low does not output test error details in log with 3.20, it did that with 3.17. Using level "Medium" introduces tons of Ncrunch internals and it is very hard to find specific test and its error output. "Summary" on the other hand seems pretty much pointless because that only outputs "start" and "stop" but nothing in between.
With 3.17 I also easily could see the error stack trace in the build log in TC UI.
2) Failed tests are no longer reported with NCrunch 3.20 (not with Low nor Medium verbosity) as they were with 3.17. See below: