Being quite neutral about the episode Digital spy explains their point of view of the 4th episode from Merlin’s season 5.

concluding: it’s a filler episode buoyed by solid performances from guest stars Montgomery and Fox – the uncle of Merlin‘s Morgause, Emilia Fox – and the series regulars never fail to impress. Not the strongest episode of Merlin then, and the weakest instalment of series five thus far, but as a piece of Saturday night entertainment, ‘Another’s Sorrow’ passes 43 minutes pleasantly enough.

The episode does not quite reach the amount of favor from the reviews as the 3rd episode but is still considered good entertainment.

Read more: http://www.digitalspy.co.uk/tv/s53/merlin/recaps/a433059/merlin-anothers-sorrow-review.html