I have just concentrated on the S-HR 24 so far as I don't install too
many high output units. The 35kw unit is exactly the same, but it has a
slightly elongated heat exchanger.

I don't think I can say a bad thing about the ATAG boilers. The units
are a slightly larger and they have a larger (80mm) twin flue system
than keston, but I have come to appreciate that a long small flue often
means noisier boiler. The ATAG units are very quiet especially as they
are running at low modulation for a lot of the time. They sell a
concentric flue, but having installed many keston c25's I now prefer
the twin flue options anyway. The twin flue system is plastic and
plumbs in easy.

You can tell a lot by looking inside a boiler and the blue angel is so
well constructed it is a shame to put the case on it. The control pcb
hinges out for easy access and layout of the boiler makes servicing
extremely easy. They have just started supplying an upgraded roomstat
(they call it a Brain!) which also provides a programming interface to
the boiler. I think they also have a solution for controlling the
boiler over the internet although I've not seen one of those units.

The blue angel boilers have a built-in 3 port valve which means
external control gear is reduced for most common installations. They
have an add-on package solution for controlling S and S+ systems. They
have a combi version in both blue angel and premier units, although if
you're in the combi market its unlikely you'd be budgeting for this
class of boiler.

ATAG boilers have been in the market for many years, although the
distribution has been limited. They are now playing catch up and
building up their customer base. I installed a Blue Angel boiler 1997
and the design has not changed since then.

I'd suggest you get some more information on the boilers and get some
references from people who have them installed. www.atagheating.co.uk
(seems under construction). Their number is 01243 673888 and if you
mention I gave you their name they might not be too surprised why they
suddenly get a rush of enquiries from uk.diyers ;-)

Martyn