I would be wary of using a stainless steel RO system. Extremely pure water tends to leach more. You may avoid a bit of plastic in exchange for heavy metals. Stainless steel tends to be 10% Nickel, 10% Chromium, which are bad and worse for you. If you do so, I would recommend getting the water tested.

Otherwise I would recommend a good plastic RO system. One where the plastic doesn't leach loads of harmful plasticizers.