I want a boiler where I can phone a local guy when it goes faulty, and he can fix it quickly, so make and model more down to guy who is installing it, last thing you want is to say install a bosch and then be told I don't hold spares for bosch. So ask the guy who is fitting it, not some one on a forum.
To be frank I look at my boiler and wonder what is made by Bosch? As it seems to be a collection of parts common to many oil boilers, and yes that is also important, say if gas, oil or solid fuel, I assume gas?