Map updates are the only thing I am interested in. So, version 12.5 is still "fine", i.e. not worth bothering, if the maps are still "woefully" out of date with the latest version.
Here's an example of how inconsistent this can be. NAV did not show a median "planter box", and told me to hang a left through the existing planter box (I went down to the corner, thank you); yet Google satellite view clearly showed the planter box. Just last week, I got "ambushed" by St. George's new crossover interchange (hate those danged things, steering you to the opposite side of the road!), even though, after the fact, I noticed that NAV showed it clearly. When I got home and looked it up on Google Maps, the satellite view shows the old (perfectly sensible) interchange, but the map view is updated to show the interchange. So, I reckon we will always be complaining about sections of road that are inadequately updated (clearly, Salt Lake County gets updated often on Google, whereas a rural area like around St. George doesn't get its satellite view updated even as often as NAV in our cars)