PRWeek spoke to agency chiefs in Manchester shortly after the crucial address, which sources said was prepared by a team including former Downing Street comms director Alastair Campbell.
Nick Williams, head of public affairs at Fleishman-Hillard, said: 'It was strong on sound bites and passion together with a few personal touches - Brown's most effective speech of his Premiership.'
David Sowells, MD of Bell Pottinger Public Affairs, said: 'It was the most important speech of his career to date and overall I think he delivered what his party was demanding of him.'
James O'Keefe, MD at Tetra Strategy, said: 'The speech was New Brown... It was full of energy, vigour and determination which was almost physically gulped down by the delegates in Manchester.'
Alex Bigg, MD of public affairs at Edelman, was slightly less enthusiastic, saying: 'He played to his strengths but he's no Blair, no Cameron.'
John Lehal, MD at Insight Public Affairs, described the speech as 'unashamedly serious, authentic and personal'.
Brown was one of many cabinet members to mention meetings with the public in their keynote speech, recounting his conversations with people struggling with bills, parents and victims of crime.
Previously, Foreign Secretary David Miliband had recalled speaking with Afghans and Defence Secretary Des Browne talked about 'humbling' conversations with the Armed Forces.
Similarly, Work and Pensions Secretary James Purnell spoke of 'a woman called Mary' who obtained a new job thanks to Labour policies.