Just came back from a 2 week trip, I bought a mobal card for myself and Ubigi esim for my parents
Having a Japanese number can be quite convenient, esp when you can use it to register for their ride hailing app (GO). I end up using it quite a lot while I was there. The card itself is from Softbank, I didnt have any signal issues
The main problem is with activation. You might have to wait up to 24 hours upon activation before you can use the card. I had to be without any data for an entire day before having it activated
You can have it delivered to your house before your trip (must buy it at least 2 weeks before), although Im not sure if activation can be done before you reach Japan
Otherwise, I collected the card the JTB counter at Narita. It ended up being a long wait because thats where you collect the JR pass as well, so a lot of people in the queue. I would opt for the free delivery option next time
Ubigi worked flawless on both iphone and samsung android. Just make sure you follow their settings step by step to get it activated