How good are Viessmann for system boilers?

tallac

I always thought Vaillant were the Rolls Royce of boilers as whenever I had a service, the different engineers that would come would always say so in some way (although this was for a combi so not sure if that changes things). I'm soon going to be needing to buy a gas system boiler and was sure it would be a Vaillant one (I need around a 30 to 35kW variant). Anyway, I've now heard people so that Vaillant are not top dog quality. Having done some more Googling, I can see that they are not bad but Viessmann seem to come on top of most lists. I'm predominately after a solid brand that is reliable and well supported.
What do people think of a Viessmann Vitodens 100-W 35kW system boiler?

Both the Vaillant and Viessmann are around the £1300 to £1350 mark, so if there are any better options for this budget then please do list them below.

Boiler will be connected to a Heatrae Sadia Megaflo (probably something like an eco 300i)

Alanp

Have had my veisseman   for 11 years now and, generally it’s been ok, had to have the pressure vessel replaced twice and had the remote thermostat go and replaced with a different make, so I don’t know if that constitutes as reliable or not, I would have another but have been recommended to get a valour ( I think) as these are supposed to be good, made in Britain with a ten year guarantee, viessman come with 5 years parts and labour, and 10 years on the heat exchanger ( or they did when we got ours) ,