It is not the greatest story they have produced, but it is certainly not the worst. Starting their Doctor Who Monthly Series with a multi doctor special was a bold choice

My main problem was that they spent far too much time trying to connect the three Doctors, failing to create a strong story. Instead, it focused on each Doctor individually for the first three episodes, ending with a weak and confusing final episode! On a technical level the sound mixing is rough at points, a few of the performances are very over the top