-
I know someone that was fitting veissman and said they were having a lot of problems and they said veissman liked to pull every trick under the sun to get out of warranting them. So I never fitted one after that and just stuck to what we know.
You're paying for the hot water on most combis, even a cheapo bottom of the range will heat most houses within reasons. 50kw seems a bit OTT imo unless you've got a massive house and now if you want tons of hot water unvented is a better option.
From my limited experience, relating entirely to combi boilers:
Result - two showers at the same time possible, no more shouting downstairs “please stop doing the washing up” etc.