I tend to agree with finnipper on this - can't really see any particular benefit especially for the majority of community fish. For Discus keepers I can see they may be useful in removing rather than detoxifying heavy metals, due to the sensitive nature of these fish, but then I'd rather go the whole hog with RO and remineralisation in that case. What is your reason for wanting to use one and what fish are you keeping?
Bear in mind that if you do, you're going to need to test the output water for chlorine to ensure you replace the carbon elements when needed, otherwise there's a risk of chlorine ending up in the tank and disrupting the filter bacteria. If your supplier uses chloramines maintenance of the HMA unit will be critical as I don't think there's a home test for chloramine to guide you on this.
I doubt the fish will benefit over and above a good dechlorinator, but if you decide to use one, Devotedly Discus sell them and are a very reputable supplier.
I have a chloramine filter, from experience now I know that it has never been exhausted before the 6-monthly change so I only test randomly now, not every time as I used to; I use DPD 4 tablets for this ?5 for 100 on eBay e.g these