[Closed] Bike computer accuracy

I've seen a few comments here and there about how GPS units are so much better than the type that use a magnet on the front wheel.

Seeing the following in a recent STW article reminded me of this:

[... GPS blah blah ...] is surely better than the tickover unit on your fork leg and that little spiky thing on a spoke that knocked it round once a revolution to record your mileage. Kind of.

Is this actually true though? It seems to me that the magnet version is accurate to within a few centimeters, or at least a few bike lengths over the whole ride allowing for jumps and wheel circumference etc, whereas there's a whole load of issues with GPS timings and accuracy (see Strava)

For speed and distance that is, obviously GPS offers more options overall.