This is mainly a negative change (higher premiums and lower payouts) and has not been accompanied by benefits such as access to a J401k account (still not possible unless the law is updated).
However we should now be able to check our pension payment history and projected payouts online at the Nenkin website.
I just called up the Nenkin hotline to ask them when I would be able to see my information, and after a brief pause to look up the answer I was told that it would be updated when I get my next Nenkin yearly report (sent out on your birthday). That would be September for me.
It seems they are rolling things out slowly. I'd be very grateful if anyone with a birthday in November or December could let me know if their info is available. Otherwise I will update in September next year :)