Valid concerns, and let me address them one by one, there are total of 16 on this list, I will make sure not to skip any. All the facts below can be verified from reliable sources. I can split them in few groups, 1. not a concern, 2. removed by stage 3 (carbon block), 3. RO required
In summary, 4 are not a concern, 7 are removed by stage 3 (carbon block), 5 can be only treated by RO type of system
Not a concern
1. Chloramine - not a concern at all, not used in Malaysia or in most of the world for that mater. In USA it is now used instead of chlorine and they have separate filters in US just for chloramine. Nasty stuff, not sure why US would use it, they say more effective against bacteria, but at a cost of being quite toxic and having byproducts.
2. NDMA - is mainly the by-products of chloramine (1) and is, again, mainly a concern for USA. It
may be formed in very low quantities when chlorine is used, however the only way to reduce it is industrial UV, and exposure to UV required is 10x the requirement to kill viruses, so no, home UV will not address it either. RO can only remove 30-50% of it. Another problem with that is that no water regulation, except California, defines any safe levels for it. But again, since chloramine is not used in Malaysia, it is safe to assume that NDMA is not present.
3-4. Arsenic III 6.5 pH, Arsenic III 8.5 pH. Arsenic III oxidizes to Arsenic V in presence of chlorine (we all do have chlorine in our water, unless your water is well water). Arsenic V at PH 6.5+ is removed by stage 2, Arsenic V at PH8.5+ is addressed below.
Removed by stage 35. VOC is reduced by stage 2 and is removed by stage 3, i.e. carbon block
6. Bromine is removed by carbon block
7-8. Mercury at various PH. It is reduced by 60% by stage 2 and to 99.99% by stage 3
9. Trihalomethanes removed by carbon block. It's byproduct of chlorination.
10. Bromate. Not naturally occurring, it is formed during ozonation of water rich of bromine. Biggest concern is actually... bottled water. In 2004 they discovered that many bottled water brands had a lot of bromate. If exposed to large doses for long time it can be dangerous. Carbon block (stage 3) reduces 60-90% of bromate, depending on mineral content of water, more minerals in the water, less is the reduction. Since water in Malaysia is rather soft, with little minerals in it, carbon block is effective. RO system can reduce up to 98% of it.
11. Geosmin, this is what gives water "earthy taste". This is also found in some fresh water fish, when some fish smells more like "mud and bog". Non-toxic and removed by stage 3.
RO required12. Arsenic V at PH8.5+. Drinking water is PH 6.5 to 8.5 and at this PH disruptor is very effective. Above PH 8.5, the only way to remove it is RO (up to 90%) and distillation (up to 98%). But if your water has PH higher than 8.5, then you have bigger concerns than arsenic, you must reduce PH.
13. Manganese nitrate. You need RO system to treat nitrate (and even that is not too effective), but these are present in well water, rivers and lakes, not in municipal water. Boiling will not help either, in fact, if any nitrates are present, boiling will increase the concentration.
14. Ferrous iron. It is reduced by 80%, so it is marked as "some removal" (significant removal would be over 95% level). Ferrous iron is not in any way hazardous to health, however it can have aesthetics effect (if it's too much, water becomes brownish). And iron in any state, ferrous or ferric is a bad bad bad thing for any filter (but again, it is ok for your health, in fact we need iron in our body). For example, with too much iron in water, RO membrane will last only 2-3 months. If it is found that your water has too much iron, then you must have special iron filter. They are expensive and even they get blocked quite quickly and cannot be cleaned/regenerated. Luckily we don't have much iron in our water in Malaysia.
15. Soluble silica. Again, silica is not bad for our body and has no health effects, in fact there are even silica supplements. However, it is called "contaminant" because it forms scale. If you have too much scale (say you boil your water and the bottom of the kettle has white deposits) then you need RO membrane. But since water in Malaysia is very soft, I'm yet to see any significant scale build up.
16. Sulfate. Again, this is not a health hazardous contaminant, but large doses may have laxative effect and give water a bitter taste. The only reasonable method to remove sulfates for home application is RO.
In conclusion, as I said numerous times, if your water comes from unknown source, you have scale problem or you want the best possible filtration you must go for RO. However, RO has a lot of disadvantages and it's a bit of overkill for Malaysia. RO makes sense in regions where water is very hard and you also need to get rid of the excess minerals. For all intents and purposes and remaining realistic, Disruptor will be one of the best under counter system in terms of contaminant removals, superior to Amway, 3M, Aquaphor or Aquasana, but still cannot match RO systems in terms of number of things it can filter out.