I replaced a Fujitsu with a Mitsubishi GE50 this week. The old Fujitsu had broken down twice over the last five years. It was in the house when I bought it, so I can't comment on how old it was. It was starting to make the same fan motor noises it made the last time it broke.
My comment on the GE50 would be I can't believe how quiet it is! The outdoor unit is significantly larger than the Fujitsu but thats ok.
Thats a good decision, new units are more efficient, quieter and have a 5 year warranty. The GE50 is I think the only 5 kw heat pump available with the small 800mm wide indoor unit. The large outdoor is good for efficiency and noise, it means the unit doesn't have to work so hard to absorb the heat from the air. Did the installer replace the pipework or use the existing?
Fujitsu premier go up to 7.2kw with a 790mm wide indoor unit
Ah yes, I just had a look at their website. I'm not that familiar with Fujitsus but have always been skeptical about their performance figures. Especially when you look at the size of their indoors and outdoor units when compared with the competition.
I can get you data to back it up if you wanted :P