Hi!
ACE-SEF seems to have problems since Joomla 3.7.x and so I want to change to JoomSEF. I am running two production websites, both have a volume of around 150 SEO-URLs, completed with meta descriptions.

I have a nice Google ranking and I do not want to loose that, when switching to JoomSEF. So my question is simple:

How can I efficiently and accurately transfer the existing URLs and meta descriptions to JoomSEF?

and further:
Should I deinstall ACE-SEF and clean up database manually before installing JoomSEF?

you are aware that JoomSEF does not work under 3.7.x either?

No, I am sorry, I did not know, that JoomSEF does not work with Joomla since rel. 3.7.x!

I have posted my question also in a Joomla forum and they answered me, that Joomla would have a new rooting scheme from version 3.8 on. And it seems to me, that Joomla did change also something on the routing scheme since rel. 3.7.x

It seems best for me, to wait for Joomla 3.8 and then make new decisions concerning a SEF-URL component. But perhaps this component will not be necessary anymore, to get "speaking URLs" without ID numbers in it.

Til Joomla 3.8, my risk is, that ACE-SEF could become instable within the next Joomla Updates or it can have security issues. It seems, that I have no alternative solution than to pray and wait :-(