Thank you for the request.
This depends on the individual ideas, the purpose and your own taste. There is no blanket answer.
18.04 is obviously the newer version.Accordingly, certain advantages and disadvantages are obvious.
For example, the newer version obviously uses newer program and library versions, newer drivers, and so on.
The downside is that newer programs typically try to meet more requirements and need to support newer hardware in addition to older hardware.Therefore, these are usually also associated with a higher resource load. Similarly, the old programs may not run on it.
However, the practical experience is that version 16.04, which will be supported as an LTS version until 2021, is much more reliable and has fewer problems than the current LTS version 18.04. With 18.04, especially with the initial upgrades, there have been a number of problems and the complaints and requests in the forum have increased.The problems have gone so far that in many cases the systems were irreparably destroyed and had to be reinstalled.
Basically, however, Ubuntu typically only has small errors in the basic run.For example, small applets in the graphical interface that do not work or lost Welcome Screen settings.
At Ubuntu, however, there are a few general problems.
If you pay close attention to this, you notice at Ubuntu, for example, that it likes to slow down between the version upgrades in the course of the smaller upgrades.
One of the biggest problems with Ubuntu is actually the upgrade process itself.Which can not only go completely wrong, but can also cause many other errors. For example, Ubuntu deletes manually installed additional packages during the upgrade, which are actually still available in the repos. Ubuntu does not give the possibility to keep them, but says, either I clean up the whole system or nothing at all in the course of the upgrade.
Ubuntu also doesn’t listen to the users and there’s a quote that says Canonical feels better than the users to know what the users want.It is interesting, for example, that Ubuntu sees Gnome as the best graphical interface for users, while many users seem to prefer other options such as Mate, XFCE or LXDE/LXQT. During the farm walk with Unity, many users even jumped off and/or changed! That’s why Ubuntu loses so many users to Mint. Because Mint simply offers what the users want and Ubuntu offers what Canonical wants.
And of course, the usual concerns include limited software repos and, above all, the data report to Canonical.
So the biggest problems are usually the basic problems, not the ones between versions.At least if you only compare the LTS versions.