Clipper is similar to myki in some ways but very different in others. You can load "Clipper Cash" and just pay for any trips out of that. The catch is that Clipper Cash isn't multi modal; if you take a trip on the BART (Bay Area Rapid Transit Subway), and then switch to a bus, you pay a second Fare for the bus. So there is no such thing as a 2 hour ticket. You can transfer from one Bus to another, within 90 minutes, but I'm not sure how well this works. Sometimes I seemed to get the second trip for free, other times I would pay. If I'd travelled on BART this would have no bearing on what I was charged on a Bus, or the Caltrain. They are completely separate "agencies" all happy to take cash off the balance of your Clipper Card.
Some agencies (eg BART) also seems to offer passes like myki pass, but getting a pass loaded seems to be a bit of a mystery. It's also not obvious if a pass covers only certain parts of the system or the entire system or if they use some other method to calculate how it would work. Needless to say I didn't bother with that and just used Clipper Cash.
The Clipper Card costs $3.00. On arrival at San Francisco International Airport we headed to the information desk near the BART station and bought our cards, topping them up with $17. This was more than enough to get us all the way to Berkeley (an hour trip) for $8.80 each. The Airport BART is a no brainer, very easy and convenient.
There are no shiny new faregates here. They all seem ancient and would appear to have had the Clipper Reader retrotfitted as per our Frankenbarriers, though the reader is on top of the gate. Every read was flawless and fast, no slowness here. There is a very small screen which shows you the fare you paid and the balance remaining on you card, just two amounts with no indication what they actually mean, but like myki most people don't bother stopping to look at it except Noobs like me!
Topping up at the Vending Machine was a similar process to how we do it, except that you actually have a choice to receive some change if you top-up with cash, though only up to $4.95 (strange amount!). There appears to be no option to receive a receipt. I only topped up with cash, and never tried EFT or Credit Card.
Using Clipper on Buses (the system is called "Muni") and also Streetcars (Trams) and another underground Metro System which is essentially underground trams, is even easier: You pay $2.00 per trip, which is charged when you "Tag on". There is no need to "Tag off" on Bus, Tram or Metro, the gates just let you out when you approach them in the underground Metro Stations. When the Metro "Trams" exit out onto the Street, you use the readers on the Tram to Tag on. Easy. Again, all readers were lightning fast, and I never had any problem.
I also used "Caltrain" which is a Vline style diesel service. When you Tag on at Caltrain (There are readers throughout the station or on the Platforms), you are charged the maximum fare to the end of the line (which is $12.75). Then, when you arrive at your destination, Tag off and are credited back the difference. I wonder if myki should do it like this on Trams and possibly Vline when it starts. Might make things easier for people to understand rather than charging at Touch off or the next touch on (and getting rid of default fares).
Of course Short Term Tickets are still VERY popular in San Francisco. You can buy a short term ticket (like a metcard) at the same vending machines as you can top-up your Clipper Card. On my brief observation, Clipper/STT use is about 50/50. Most tourists don't seem to bother with Clipper and just buy tickets as they go. The lesson here for Melbourne is painful, and obvious.
I didn't actually buy one but on buses I watched people buying tickets, the drivers seem to have almost a mini vending machine which customers feed coins or small notes into and are then sold a ticket, the same on the Streetcard/Trams. On the Metro, you need to prepurchase your ticket before boarding.
You can also use Clipper on the famous San Francisco Cable Cars. It's $6.00 for a one way trip, charged by the conductor to your card from a handheld reader.
I registered my card on the Clipper Website, again, similar to myki. All hardwired transactions (eg from readers which weren't on a vehicle like a bus or tram) appeared almost instantly on the website, no 24 hour or longer wait. You download transactions in a PDF.
Online top-up apparently can take up to 5 days(!). Autoload would appear to be very popular.
Due to the nature of the separate transit agencies in San Francisco and the non multi-modality, if you are travelling a lot it can get very expensive very quickly. In the 6 days I was there I was travelling all over the place, and I spent a grand total of $110.50 (ouch, seems expensive!) Though having said that, having to buy separate tickets for each mode of transport I used each time would have been quite painful, and no cheaper.
Compare that to myki and skybus. If I'd visited Melbourne, and used Skybus, and myki money, and done a day trip to Ballarat on Vline, it would have cost me about $95, so I guess not that much difference.
Making a direct comparison between the two systems is difficult. On reader speed, Clipper wins hands down. It was consistently fast and problem free. I put it in my wallet in the same place my myki normally lives. I saw people have way more problems with short term tickets than with Clipper.
If you look at Fare Structures and how you are charged, myki wins easily, though that is a completely separate issue to the technology in use.
Trivia: A myki held to a clipper Topup machine tells you to "See attendant".
And why did I take that Caltrain trip? To get this shot, of course.