Whenever Apple launches a new product, reports of problems with new and old features alike begin to stream in, and the two questions that we always ask are whether they’re widespread, and whether they’re due to user error, software issues, or hardware issues. For instance, iPhone OS 3.0 Wi-Fi problems were so widely reported by iPod touch-using readers that they didn’t seem isolated, and we’ve had the same issues ourselves—clearly not hardware problems because Wi-Fi worked perfectly on the same devices with the prior 1.0 and 2.0 versions of the OS.

We’ve noticed that the iPhone 3GS compass is having some issues, too, though the scope and cause of those issues is difficult to quantify. The 3GS units we’ve tested have showed a fairly obvious unreliability in getting Maps or even their own Compass apps to agree on what the “right direction” is, and appear to have a very high degree of susceptibility to in-car magnetic fields. A week or two ago, we stopped by an Apple Store and put three 3GS units on a counter in the same direction, finding that their compasses all seemed to be pointing in somewhat different orientations that were off by single- or double-digit degrees. Repeated re-tests of something we noted in the iPhone 3GS review—Maps’ tendency to show north-south movement down a street as diagonal motion rather than northerly when the compass is activated—have continued to yield the same results in our test cars.

Now there’s a game out, SurrounDEAD, that optionally uses the Compass for its movement control scheme. It places you in the center of a city filled with zombies and challenges you to turn around and shoot them before they grab you, which they can do from your front, left, right, or back; constant turning is necessary to stop them. With the default control scheme, you turn by tilting the iPhone, which works, but the compass requires you to actually spin around, and all too often doesn’t appear to be properly registering movements. It’s like what we saw when driving around in cars with Maps, only zombies are eating us alive because the compass is wonky.

Our hope is that Apple will correct these issues with an OS 3.1 update, but the question of whether they’re truly software or hardware specific is going to remain a mystery until then. In the interim, such issues do raise a concern that prior “it just works” Apple products haven’t faced for any significant length of time: how many months should users expect to have to wait until a promised feature of the device or software they just purchased works properly? When an iPod touch’s Wi-Fi goes out in 3.0, but works in 2.2.1, should users be expected to downgrade? Has Apple tested the 3GS compass enough in its labs to know that it can correct whatever the issues currently are? We don’t have the answers, but as users, we’re as anxious as you are to find out.