Advice on which SEF extension to choose

Hi,

As far as I know, Miwisoft has discontinued their Joomla extensions several years ago.
And if you look for the changelog for MijoSef, it seems that no new release have been out since 2018:
miwisoft.com/support/docs/mijosef/introduction/changelog
I would highly recommend to not use it. It might have security issues that have been discovered since then but haven't been fixed, and using it on Joomla 4 will be impossible the day you decide to migrate.

I'm not familiar with JoomSef, but never heard anything bad about it.

Regarding Sh404SEF, it's a double-edged sword. It allows you to have any SEF URL you want for any page on your website. So if that's something you need, it's great. It's a powerful tool. However, this means that it saves the correspondance between the SEF and non SEF URLs in the database. And thus, when you change your menu items, products settings, Joomla article settings, you might face 404 errors as the correspondance needs to be updated in Sh404SEF.

Now, I would personally not recommend using a SEF URL extension if you can. We don't use one on our website and it works fine. It's a bit more difficult to setting Joomla / HikaShop to get the URLs you want, but then I think you have less pain in the long run. And in the end, the fact that the URL is a bit different from what you envisioned probably won't matter at all for your website SEO.

I'm not a SEO expert, however, any such expert should tell you that what matters most for SEO is the content, not the URL itself. So rather that spending days or weeks configuring a SEF URL extension and have to maintain it in the long run, it might be better to work on the content of the website itself.