dcullen, I did extensive research and opted for a top of the range which I found at half price on the net. Bottom to mid range is single filter, so when it is being flushed water supply is interrupted, flush is set by timer not volume of water softened so it could be flushing too much (when on hols) or not enough (when you have guests = heavy usage), need electricity supplying to it.
Top of the range means; dual filter so that when one is being flushed the other maintains your water supply. Only flush when needed based on volume of water passed through filter rather that elapsed time (all that filter flushing whilst on holiday etc = more salt used), no electricity supply required as mains water pressure drives all functions and it actually fits inside a standard kitchen unit, many don't or the instructions (only after you've bought and opened it) tell you to cut a hole in the base of the unit. Plus it takes any type of salt, block, granule etc and has easy front top lid access for topping up. I have a 4 bed, 3 occupancy household with a heavily used power shower and it takes a 10kg bag of salt (£3.98 from Q & B shed) every 4 weeks, less than £1 week and as I said earlier, all the other detergent / soap savings but most of all all the time spent cleaning is saved and every thing stays cleaner.
Get on with it man, which one is it they all shout.
This one here;
http://www.emwc.uk.com/Details.asp?ProductID=87
and I see its still half price N.B. this is a genuine half price for the specification based on all the comparisons I did.
emwc is the east midlands water company and I have subsequently had very good email support from them (nothing wrong with product, just questions on my slightly peculiar set up).
I would also recommend paying the £29 or whatever it is for the specific valve and flexi pipe installation kit for 2 reasons. 1) you get nicely labelled valves. 2) More importantly, the very robust flexi pipes maintain an internal diameter of 15mm so don't restrict any water flow unlike the ones bought from the diy sheds which have 15mm connectors on them but the internal diameter of the pipe and fittings is significantly less.
P.S. Other than the salt top up, I fitted it and forgot about it......