I was invited to apply for the Apple Card early, so I've had time to experience the entire cycle through to paying the first month's bill. Here are my thoughts.
The approval process is amazingly swift and easy, because Apple already have your details from your Apple account (iTunes, app store). You apply right from the Apple Wallet app, and get an answer instantly.
The cash back and interest rates are nothing special. I got 12.99% APR, which is the base level; it goes up as far as 23.99%. That's better than my AmEx APR, but the AmEx offers more cash back in everyday use (3% at supermarkets and gas stations). With the Apple card, cash back is credited at the end of each day.
The card is surprisingly hefty. I'm not entirely convinced I wouldn't prefer a plastic card. We'll see how it holds up after a year or two, I guess. Enrollment is a matter of opening the Apple Wallet app and holding your phone over the new card in its envelope. No phone calls with annoying recordings trying to upsell you things.
The card has no numbers on it. No card number to steal, no CVV. It still has a magnetic stripe and a chip. You get an extra 1% cash back if you use Apple Pay rather than the card; clearly the intent is to get consumers to push stores to accept Apple Pay and other NFC-based wallets, as many US stores have been slow to get on the contactless bandwagon. (I'm looking at you, H-E-B.)
EMV transactions with the card seem to run through faster than my other cards. With AmEx it's not unusual to have to wait 2-3 seconds for the POS terminal to tell me I can remove the card; with the Apple card it has been happening so quickly that at first I thought it was telling me there was an error reading the card. I don't know whether Apple are using a faster, more expensive chip on the card or whether Goldman Sachs have heavily optimized the back end, but whatever the explanation, I like it.
Transactions appear in the wallet app immediately. This also happens with AmEx if you add your AmEx card to your Apple wallet. However, with the Apple card your transactions are instantly categorized, and you can see the percentage cash back you got for each one. Tapping on a transaction takes you to a screen showing the location where the transaction was made on a map with the full name of the commercial entity, and even a photo of the store or restaurant. The app design is the best I've seen for a financial app.
You get warning notifications before each bill, and a notification when the bill is actually due, which is always on the last day of the month. The app defaults to assuming you want to pay off the entire bill each month, and encourages you to do so, telling you that's the best way to avoid any finance charges. Paying the bill requires your routing number and bank account number. If you want to do it some other way, you can download a PDF monthly statement. (The monthly statement is also a masterpiece of clear design.)
No foreign transaction fees. This is huge if you're someone like me who travels overseas fairly regularly (or buys music from foreign bands on Bandcamp, or buys cheap stuff on eBay).
The data about your purchases is kept on your phone, encrypted. While Goldman Sachs have your transaction history, they're contractually obliged not to share it with anyone for marketing purposes.
If you need to talk to customer service about a suspicious transaction, you can message them from the wallet app.
The one obvious downside: You absolutely need an iPhone to use Apple Card. There's no web site.
Overall, this is a credit card designed around what would be best and most convenient for the customer, rather than the bank. Even if you hate Apple, you should be rooting for the Apple Card to be a success, so that the other banks are forced to improve their user experience.