I have tried some currency converters available in the App Store, but I find this one undoubtedly the best one of all.
Im a long time user of his Mac OS widget, and when he made an app available for the iPhone I had no doubt about purchasing.
However nowadays with iOS 8, great iPads and iPhone 6, its hard not to feel a bit sad this app doesnt have an improved look and, specially, an universal version.
In my iPad Im using another currency converter exactly for this reason and although I happen to like it I still very much like this one.
Please update it, and you will get restored the 5 stars you rightfully deserve.
kaarlows about Currency Converter - Money Exchange Rates for more than 220 currencies!, v4.2