OK, yes - manual here, There seems to be just one high temperature unit in the range which has a CoP of 2.61 at both A-2W65 and A7W65 which is reasonable I suppose. Otherwise CoP’s seem to be just over 4 with 7° air and about 2 with -2° air for a 55° flow temp - again not radically different to any other unit on the market.
I did some back of the envelope calculations in the previous thread which suggested a “seasonal average” CoP of 3.6 would reduce your COs footprint by about 20% but probably cost more to run than a gas boiler - at least in the UK, for mains gas.
Your comments re underfloor heating being well suited are spot on, of course - as are your observations that it’s a complex decision if replacing a conventional boiler in an existing system.