My Sena case was too flimsy and didn't ultimately survive the test of time, which was short given the fast turnaround between iPhone models. I had both the wallet slim and the flip versions. The flip version lacked any way of holding the phone in when the clasp was undone, which was a flaw, while the wallet version was actually quite good at holding the phone in with Magia tape. It worked extremely well. Ultimately though, the durability on both was not great.
Enter Hex cases. I have purchased the Icon Wallet for the iPhone 4, 5, and 6 and have been extremely impressed. While it's expensive after shipping and currency exchange, it is the best case I have had and allows me to avoid the Costanza wallet.
The Icon holds three cards and about three bills and a few receipts comfortably. Don't get me wrong, this is a minimalist wallet, but it lets you carry the basics.
The last couple of times I have ordered directly from Hex, but in Canada brokerage charges and customs fees add to the cost and make this wallet more expensive than most. Next time I'll order from Amazon as it looks like there are some more cost effective shipping options to Canada.