between vaillant and worcester i believe both have advantages and disadvantages
vaillants are a bit of a struggle to fit i find, tails to close together to get spanners in comfortably and awkward to fit, but good boiler and designed to be super easy to work on afterwards, changing a HW heat exchanger is a simple job for example, customer service is mediocre, be careful even if u tick the box on registering the warrenty that you will take up the servicing then they still send a letter to customer offering there services etc.
Worcester
agreed alot of plastic inside but i am fitting alot of these at the moment, i believe a quality boiler with a a name the customer feels confident with and a 5 year warrenty with excellent after sales help!!
very easy to fit! telescopic flue etc
defo more awkward to work on after!
And as a cheaper option to customers i offer a Main combi he
i quite these no frills boilers pritty decent boiler which is basically a baxi,
managed to get 2yr warrenty and loads of free spares out of the rep in my area aswell,,
bloody heavy though lol