I have a Lezyne Mini GPS ('year 9' version), got it cheap last winter when they were being sold off ahead of the 'year 10' version's release.
It's good but the battery life is poor in cold weather, specs quote 10 hour battery life but I was lucky to get 6 hours in the winter, which barely adequate for my winter rides, seems to be nearer to 10 hours now that we are in summer though.