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!
But do you not get what you pay for. Generally if you want guarantees then you pay for them. Often guarantees are not worth it. I think of them as an extra payment for an insurance policy that my premiums won't go up. How much cheaper is the reviewable product from Friends First or Irish Life? Then you can decide if you want to pay the extra for the guarantee. Remember you are paying extra from the start and in every year. You would want to weigh that up against the extent to which your premiums MAY increase to if the companies decided to review them. You say that Friends First or Irish Life MAY review their premium rates - interesting to know how often they have done this and by how much the rates changed?