I bought 1 from Ebay a few years ago, very similar to the 1 you linked. I also have the water storage tank like Scott mentioned.
1 thing to remember, in a few years the only thing you will have original from the unit are the filter canisters. All the filters will be changed out, so in that respect, there is really no difference in any of the
RO/
DI units beside the capacity of the
ro membrane and the quality of the replacement filters.