I reviewed Apple’s iOS 6 this week, and one of the areas I focused on was the new Maps app (the Google one is gone, allegedly because Google were being dicks about their mapping API).

It’s an important app, and I set out to see if I could break it. I used a quarter of a tank of diesel trying and failing to confuse the turn-by-turn navigation in and around Glasgow and its suburbs; I deliberately asked it for directions to places where the roads have been significantly changed in recent months; and I threw loads of randomly chosen addresses and businesses at it to see if it got them right.

With a few exceptions – businesses shown in slightly wrong places on the map, one result that was completely wrong – it performed really well. If it knew about the new roundabout they’ve just stuck between Milngavie and Clydebank, then clearly it was safe to assume that it knows where the big stuff is. As I wrote in the piece:

We half expected an app that was just great in America and utterly useless in the UK. We were wrong.

…Maps is a decent app, but we think existing, dedicated sat-nav apps have more finger-friendly UIs and more features, even if they do charge for traffic data – and if you’ve got an iPhone 3GS or 4, those apps are your only option.

Over at the Guardian, technology editor Charles Arthur took a similar approach and came to similar conclusions. Like me, he wrote:

it’s very good. Here we need to distinguish between the maps themselves, and the maps app. The maps don’t have all the highlighting of Google’s, but the amount of detail such as road names seems to me greater… [it] brings feature parity with Android – as does the introduction of turn-by-turn voice navigation, so that your satnav can now play music and make or receive phone calls.

It looks like Charles and I were lucky, because as we’re discovering today the Maps app contains lots of problems. My personal favourite is that it lists Our Price branches; for younger and/or overseas readers, Our Price was a record shop chain that closed almost a decade ago. Some towns are missing altogether; other sensible queries don’t work unless they’re phrased in a specific way (eg “Paddington” doesn’t work; “London Paddington” does); and sometimes the context awareness is broken, so a UK user searching for Christchurch near Bournemouth gets directions to New Zealand.

What’s interesting is that in many cases, it’s the populous areas that have the problems: apparently Leeds is particularly poor. I came to Maps assuming that the big places, such as London, would be perfect, and that if screw-ups were to be found they’d be more likely in more northern and more rural areas – so I went looking for such screw-ups and found they were relatively rare.

It’s clear that Maps has been rushed out, that some of its data is inaccurate and/or ancient, and that it’s going to be a while before it’s as good as Google’s multi-billion dollar mapping system. Apple doesn’t screw up like this very often: the last one like this I can remember is MobileMe, whose unhappy launch led to an unhappy Steve Jobs making the relevant employees very unhappy.

Maps will get better, but the issue demonstrates something important: individual journalists and bloggers can’t cover every conceivable use case for technology products, and sometimes problems don’t emerge until a product has actually been released.

If you’re considering spending lots of money on something, or if an upgrade is replacing a feature you rely upon, it pays to wait.