Out in the FieldCurrently PayPass readers are available mainly at major retailers, but a few small vendors in the San Francisco area do take PayPass--such as Cafe Blanco on Sutter Street in SF's financial district. My first purchase was there, and I ordered a latte and a croissant. The manager of the store was working that morning and told me that many of his customers use his cafe's PayPass reader with their NFC-enabled credit cards, and he'd never had any problems with receipt storage. On my end, paying was easy: The phone gave a quick vibration, and the reader beeped when the transaction happened.The purchase required a signature, so the manager printed out a receipt and I signed it. Having Google Wallet didn't make the transaction itself any quicker, but it was easier just to reach for my phone to pay instead of digging around in my backpack for my physical wallet and credit card. On a recent Friday afternoon I took the Google Wallet app out again for more sustained shopping. My first stop was a Whole Foods on 4th Street in San Francisco, where I grabbed an onion, some asparagus, and a bottle of wine for dinner. Payment was as easy and effortless as it had been at Cafe Blanco, but the cashier seemed to my ability to pay with my phone, which surprised me a bit. But one of the great advantages of Google Wallet is how natural it starts to feel. Once you've paid with your phone a few times, or have seen a phone payment, it starts to become as natural as pulling out an old-school credit card. I also had installed a bandwidth monitor to see just how much data the app would set you back per payment--248KB, as it turns out, which is about half of what it takes to upload a photo to Facebook from your phone. Luckily, Google Wallet doesn't appear to be a data-eating beast. As I left, I noticed that the balance on my Google PrePaid card hadn't deducted the $13 I spent at Whole Foods, which was slightly disconcerting. I exited out of the app and hoped it was just taking some time to refresh. After Whole Foods I stopped by an Office Depot near Market Street to purchase some batteries. I had been in there several weeks before and tried to buy pens with an earlier version of the Google Wallet app, but the PayPass reader had been malfunctioning. Nothing changed this time, either: I held my phone up to the reader, and there was no vibration or beep. "None of these ever work," said the cashier, who declined to have her name mentioned in this article. "Customers are always frustrated because they hold up their card and nothing happens," she told me apologetically. I was frustrated, too, as I dug around in my backpack to find my wallet at the bottom of all my groceries. I then ran down to Peet's Coffee on Market and 2nd, which had just received brand new PayPass readers. I arrived that afternoon with the Nexus S and ordered an iced coffee. I opened up the Google Wallet app and noticed the balance on my prepaid card still wasn't correct, but I knew I had enough to pay for the coffee, so I tried to pay hoping that another transaction would right the balance. This time, there was a beep, but the phone didn't vibrate. After a moment the cashier said, "Looks like the payment was denied. PayPass must be having early jitters or something because a guy came in here earlier and tried to tap his card, and the card was denied, but when I swiped the card, it went through." I ended up paying with my debit card, again.As far as I can tell, neither of these two failed tap-to-pay experiences were the fault of Google's app, but rather the fault of the PayPass readers in the vendor's stores. But it would behoove Google and MasterCard alike to make sure that vendors know who to call when something goes wrong with their readers, and to have vendors teach their cashiers how to restart a malfunctioning reader. As long as paying with a credit card is a more consistent experience, Google Wallet won't revolutionize payments, and will merely remain an alternative for the most tech-savvy consumers. Soon after I was declined payment at the Peet's coffee shop, the balance on my Google Prepaid Card corrected itself, and showed that I had a little over $4 left. Over the weekend, I took the Nexus S phone to a CVS pharmacy in Oakland and grabbed some razors and cereal. Together, the items cost over $5, but I wanted to see how the app reacted when I went over my balance on my Google Prepaid Card. As it turns out, the transaction was amazingly easy: I held my phone up to the reader; it vibrated, and the reader beeped, deducting $4 off my bill, and allowed me to pay the rest of the bill in cash. The ease with which this worked amazed the cashier, who commented, "Wow. You're the first person I've ever seen use a phone to pay for things." One thing is certain: When Google Wallet does work, it makes you look very cool.The Bottom LineGoogle's Wallet app is a really easy way to pay for things when it works, and when the app itself stalled, it corrected the error relatively quickly. The weak link in the chain are the vendors' PayPass readers, which need to work better, or be easier to service. Of course, Google Wallet is brand-new and available only to a limited audience at the moment, so the tap-your-phone-to-pay experience has room to grow. Hopefully the problems I experienced will get worked out over the coming months. Google has said that it hopes to to other phones, carriers, vendors, and credit cards, but until then, the tap-your-phone-to-pay experience will remain a novelty, and a secondary form of payment.