Q: I’m a long time reader, first time mailer (can’t say caller can I?) I have always read your articles especially regarding accessories, however I still use an iPhone 4 and I’m looking for an attractive, yet professional iPhone 4 case that has a card holder slot so I can use my RFID Public Transport ticket system (MYKI, Victoria AUS). I haven’t had too much luck in finding one. Do you have a recommendation for what I can use? I saw an XtremeMac Form Fitting Flip Case however I don’t want the flap as I find these a pain to use.

– Bradley
A: There are several cases for the iPhone 4 that include card holders and are worth considering, although almost all of them come with at least some compromises. On the leather and faux-leather front, check out the Sena Cases WalletSkin and WalletSlim, CM4 Q Card Case and Twelve South BookBook.
Plastic/rubber options include the Case-Mate Pop! ID, Incipio Stowaway and SwitchEasy Card.
While each of these options pretty much work as intended if your primary goal is to carry one or more cards around alongside your iPhone and have easy access to them, they’re not the best cases that we’ve reviewed in terms of overall protection and functionality. Some, such as the BookBook, block the iPhone camera entirely and employ a flap design that inconveniently covers the front of the iPhone. Others simply don’t offer as much protection as they should or sometimes needlessly increase the thickness to make room for the cards.
Since you’re dealing with an RFID card specifically, another option worth considering if these options don’t particularly appeal to you is to simply use one of any number of normal iPhone cases and simply sandwich your RFID card between the back of the iPhone and the inside of the case.
How well this works will depend on how snugly the case fits, but one of our editors has successfully used this method with a Zipcar RFID card and cases such as the Speck CandyShell and CandyShell Flip—most RFID readers should have no problem reading your card through the back of any non-metallic iPhone case, and it’s a viable option if you only need to scan the card against an RFID reader and rarely actually remove it from the case.