They are OK. I find Sydney ones more reliably tap, plus you can use just a credit card to tap, as well as use a credit card to buy the Opal card. You can buy the opal card at 100s of places not just train stations. The actual transport itself is better in Tokyo tho.
I like how in Sydney you can just tap on and tap off (in a lot of situation) without a gate. Like the light rail, you don't have to have all the pressure of getting through a gate with 100 people behind you like in Tokyo.
When your card fails in Tokyo, it's such a stressful event, and you have to do that "huff, turn around & stomp off" thing everyone does...
