I'm currently using eSpring because I'm just like you, looking for POU water purifier with NSF certified. I do a lot of studies and research and finally end up with picking up the eSpring with trade-in with my existing water purifier with rebate up to RM600 around 3years ago.

Tupperware NanoNature water purifier are almost identical to Amway eSpring water purifier. I do studies on the Tupperware one because last year I was approach by one of their agents. But they can't provide me those performance report that claims by them. eSpring got full list of performance report printed on their brochure black and white, and even link to the source where those claim came from. The so called optional alkaline crap thing on the NanoNature is not NSF certified or not even FDA approved.

Of course, you might thought of eSpring is expensive but I think the NanoNature not cheap either. Their RRP is at RM2800 while eSpring member price should be at RM3200, sometime eSpring got promotion like new member sign up get discount rebate or trade-in offer. I choose eSpring is because I trust their company technology and credibility, more over the eSpring is full unit NSF 42, 53, 55 certified direct printed back of the water purifier. Not like those OEM X-brand simply put sticker on their product claim everything like pro but only component certified or not even have tested.

Not so sure about the Tupperware warranty/services but you can find out more from them, Amway provide 2years warranty and sales after service as well, you can even DIY replacing the filter and save yourself a lot of service fee.

Hi kwchan, i am using Cleansui by Mitsubishi Rayon. This NSF certified is about RM1500, include undersink installation. maintenance is easy (no backwash etc) just change filter every year or two (filter below RM400) . No crap join member or alkaline.