We have a fixed bed Swift, very similar in layout to the Charisma, with corner toilet/shower compartment, and it's fantastic. We've owned it for 7 years now, and are thinking about replacing it - not because we don't love it, but thinking long term about retirement and buying now whilst we can afford to buy new. We've had a few faults, but nothing major, and everything has 'worn' very well. We've had two week holidays in France, twice a year since we've had the Swift, plus many weekends and other weeks away, so it's been well-used, including in the cold over New Year on one occasion. We've had to replace the tyres twice, and had two bumps where bodywork needed repairs, but other than that all the original equipment is still working. An exception is the water pump which we replaced voluntarily because when it didn't work my partner stripped it down, and found it covered in black mould inside. We've had no damp at all - and the only modification we've made to it was to fit a Mini-Heki over the bed where there was just a normal roof-light. Ours doesn't have all the bells and whistles of your dealer special, but it is unusual in that it was a continental model, which Barrons were selling, with the door on the wrong side. It was also a bit wider than the British Swifts of the time, so has a feeling of space (which the newer Swifts do any way).
There are two of us, and not having to make the bed up each night is a real boon. I always wonder what sort of sleeping arrangements those who say 'the one on the inside has to climb over the other'. All the caravans I've seen where you convert the cushions to a double bed have 'one person on the inside' - I can only presume they sleep separately on the bench seats at the front.
From my point of view I'd say go ahead - but there will always be others who've bought the 'Friday afternoon Swift' who point out all the problems they've had with theirs. Hope you enjoy the new van.