  We present a comparison between the performance of a selection of source
finders using a new software tool called Hydra. The companion paper, Paper~I,
introduced the Hydra tool and demonstrated its performance using simulated
data. Here we apply Hydra to assess the performance of different source finders
by analysing real observational data taken from the Evolutionary Map of the
Universe (EMU) Pilot Survey. EMU is a wide-field radio continuum survey whose
primary goal is to make a deep ($20\mu$Jy/beam RMS noise), intermediate angular
resolution ($15^{\prime\prime}$), 1\,GHz survey of the entire sky south of
$+30^{\circ}$ declination, and expecting to detect and catalogue up to 40
million sources. With the main EMU survey expected to begin in 2022 it is
highly desirable to understand the performance of radio image source finder
software and to identify an approach that optimises source detection
capabilities. Hydra has been developed to refine this process, as well as to
deliver a range of metrics and source finding data products from multiple
source finders. We present the performance of the five source finders tested
here in terms of their completeness and reliability statistics, their flux
density and source size measurements, and an exploration of case studies to
highlight finder-specific limitations.
