Just came back from Japan (mid-July) and this was my experience with Revolut:
-No problem at all with ATM withdrawals at 7-Eleven. I have a Visa card and they charged 216 yen per transaction (regardless of the amount). My friend has a MasterCard (standard plan) and she was charged nothing
-I was able to pay everywhere where they accepted cards (Tokyo, Kyoto, Nara, Koyasan, Kanazawa, Takayama).
-I changed to yens when the exchange rate was more favourable before travelling there (I had set an alarm for a exhange rate).
-I always made sure I had yens in my account (exchanged in advance) so I never had to pay in EUR on a weekend, when Revolut applies a fee as the European markets are closed (Weekend exchange-rate surcharge clarification).
In short, it worked perfectly