Having used variant RFID cards in three different systems recently, I can add a few comments.

1. No matter how well they work you will get complaints, some valid, some not.

2. Once you get used to them they make life easier.

3. One of their reasons for existence is to make disparate systems transparent to the user.

The three systems I have used recently are the Los Angeles TAP Card, the Bay Area Clipper Card and the Netherlands OV-chipkaart. They are used similarly but have their own idiosyncrasies.

I use the Clipper Card regularly, actually a Regional Transit Connection card as I am over 65. This is being phased out and replaced with a Senior Clipper card (no photo on the card). This gives one a 62.5% discount on BART and 50% on most other operators compared to a regular Clipper Card.

The MTC wants this to eventually work with all Bay Area operators. My card is tied to my bank account and $50 is added when the card gets below $10. Very convenient as you don't even have to take it out of your wallet. Just "tap" (hold) your wallet against the reader until it beeps.

For those operators with a fixed fare (AC Transit, MUNI) you tap on entry. For operators with zone or distance fares (Caltrain, BART) you tap on and off. Transfers and discounts are automatic. You can also store passes of various kinds on the card.

The LA TAP card works similarly but one can buy a standard card from a vending machine ($1) and put a senior fare on it ($0.55 peak, $0.25 off-peak). Regular fare is $1.50. Most transfers require another full fare. If you live in LA and are over 62 you can get a senior card and put money on it. You will then be charged senior fares automatically. Cards can't be connected to a bank account.

The OV-chipkaart is a national card. It is good on anything that runs on the ground or water. This includes buses, trams, ferries and inter-city trains. To get a senior discount here (34% off) you have to have a Netherlands bank account, although there is an exception for those living in adjacent countries. So tourists pay full fare, $1.15 to board + so much a kilometer. The later depends on the operator. You always tag on and off, with the exception of changing inter-city trains.

All three systems still are expanding and working out bugs. The Netherlands is going to upgrade their cards because of security problems (code cracked) and occasionally somebody gets charged a euro or two too much (or too little).

The California systems may have to upgrade because every operator/district wants its own rules and fares and the storage limits of the card may get in the way.

I wonder how many decades it will take to have a national card here.