So rail blocks is better than IOTA is that what are you suggesting? I see it has no fees, free transactions which is awesome! How private it is I tend to think privacy coins are way to go like Verge, zcash and some others, this is why I haven't been interested in iota in the first place because I will have to use mixing service that will have its own fee plus on top of that mixers are centralized.
I tend to disbelieve when any coin at all is provided "without fees". The transactions, the infrastructure and many other things have a cost and eventually the user has to pay one way or another. Else, someone is not getting a fair deal.