Originally Posted by jib71

They're issued by different companies but to all intensive porpoises, they're the same. Both cards will allow you to ride buses and trains in the same way. Any taxi or store that accepts one for payment will also accept the other. Both expire after 28 days.

BTW - Don't be afraid to use taxis for short hops in cases where public transportation links aren't optimal. Initial flag fare for a taxi will cost you less than subway fares for four people. What's more, you'll each pay two fares if your journey requires you to change between two different transit companies. A nearby location that requires a short subway ride and then a short JR line ride, might cost your family 1,400 yen in rail fares. For that money, you could travel about 3km by taxi. Regular taxis will take three people in the back and one in the front passenger seat, and almost all accept SUICA or PASMO for payment.