I’ve always used an Autopen for my Lantus, so I can’t offer a comparison.
My one complaint about the Autopen is that the numbers completely wore off within about a month, so all dosing now is done by counting the clicks alone, which are 2 units a pop. No big deal really. The whole thing feels a little bit cheap and plastic, compared to my [oooh, luxurious] HumaPen Luxura, but hey.
I reckon if usage warnings make it as far as becoming NHS warnings, then switching would definitely be advisable.