I have had a Worcester Bosche Fitted exactly 1 year ago and it is Brilliant, Masses of hot water within 7 seconds and heating that is remarkably effective, It is very near silent in operation and I am Highly delighted with it. It's just been serviced and the engineer said it is just like new.
Originaly I fitted my own complete system with 12 rads on three floors of the house. I put a Sime conventional combi in the little bedroom at the top of the house which had two breakdowns in the 6 years it was installed, it was Very noisy in operation so deciding to fit a condensing boiler, I had it fitted in the downstairs toilet which is nearer the kitchen and bathroom. I am really glad I picked the Worcester, it fits well, is smaller then the Sime and you can fit it in a cupboard.
Very economical to run too.
Hth
Pete