"Let's start with the frequencies supported by the phones. We're used to quad band GSM smartphones, so the loss of one of them in the ZTE Racer (sometimes known as the ZTE X85)) makes it a tri band (900/1800/1900) model. If you are going to be travelling, you might have to do the old fashioned thing of checking the frequencies of the networks you'll be roaming on.
The Nokia 5230 covers all four frequencies, so is pretty much a global phone and if you're a international frequent traveller this could be an important consideration. But what the 5230 gives with one hand, it takes away with another. The 5230 does not have Wi-fi."