Currently 25% off... free P&P and PayPal friendly :-)
I have owned one of these for about 5 years now and have had many positive comments about the quality of the water when visitors drink from the unit. It really helps if you live in a hard water area, but is really only suitable for a single person or couple due to capacity. It is a gravity filter, so the water drips through slowly into the lower chamber, but once the unit has been in use for a month or so, the water feeds through at a reasonable rate (although I haven't timed a litre, its perfectly acceptable).
You can also add a fluoride/advanced filter.
You can even filter contaminated water - more technical details & reviews available on-line.
Other larger units available & a reliable company.