Haven't used them myself. Found their holiday insurance quote slightly higher than going direct to the crowd for whom they were reselling (ACE Travel Insurances) but not sure if the same applies to their home insurance policies. This topic might also be of interest:
I'd be more inclined to say "shop around" as no single broker or underwriter is guaranteed to be cheapest (or best - not necessarily the same thing) in all cases.
Just shows that each individual needs to shop around - nobody, including 123.ie who were generally significantly dearer for equivalent cover, could beat AA/Royal & Sun Alliance for my requirements up to this year when FBD bettered them.
Its always worth shopping around. I recently had to renew our home insurance, cheapest was 123.ie next cheapest was fbd. Last year was with eagle star who were not competative at all this year.
I have used them. For Motor Insurance drop the Windscreen protection option you'll find that they return very competitive prices from a British insurer called Highway insurance(although the insurer won't be identified) which comfortably undercut the cartel operating in Ireland.