To try and get back to the original question, as far as I know, FF are the dominant provider for PHI cover because they are the only ones to provide an option of a guaranteed premium level, ie, unless indexation is chosen, the premiums WILL NOT increase for the duration of the policy. This is a very popular option with many customers looking for certainty of cost. FF also offer a 'reviewable' premium option whereby FF will review it every 5 years, and if they deem it necessary (depending on their claims experience etc) MAY increase the premium rates. This option therefore starts out at a lower premium than the guaranteed option, because there is an option to increase it over time.
Irish Life will only offer a 5 year or 10 year reviewable option, ie, no guaranteed option. Horses for courses....don't just decide on price, etc!