IOTA is untested and IMO unnecessary. The DAG structure has inherent problems.
Satoshi pay is just looking into using this for micropayments but really the future is in other technologies that are 'on chain'.
Just have a look at https://bitcointalk.org/index.php?topic=1354220.1200
Ehh LN is cool but it does not solve all problems. Also it is inherently centralizing.
https://steemit.com/bitcoin/@kyle.anderson/fork-christ-s-sake-bitcoin-is-going-to-fork-is-segwit-bitcoin-whose-side-should-i-be-on
agreed. but it has can excel in some specific use cases like micro-transactions, but nothing is without a cost (centralizing).
about IOTA (i'm not very familiar with that one yet but it seems quite promising), what are the problems you are referring to?
Haven't seen any compelling game theory of their Tangle. Can't do smart contracts - by design. Also DAG structures are vulnerable to "becoming spread too thin".
Interesting experiment. Really shouldn't be given more status than just that.
yoooo