I've been a user of sh404sef for some years and overall have found it to be a good product. For this reason I purchased subscriptions when the component went commercial. Recently more of my clients have had Virtuemart stores and whilst sh404sef allows you to fully manage the Virtuemart URL's and meta data, you cannot amend the page titles for Virtuemart without hacking the sh404sef core. Not only is there no instruction provided on how to make the changes (you are only advised which file to target) but forum topics on the issue are shut down and email requests to advise whether there are any plans to develop Virtuemart page title management (in the same way as Virtuemart URLs can be managed) are completely ignored. So while I think this is a good product, I find the developer's attitude/approach to this issue somewhat disappointing, and while I continue to hold a subscription I would jump to another product if the Virtuemart page titles could be managed.
Sorry you're (at least partially) unhappy with the extension, but what you report here is simply totally untrue. You can absolutely and positively manage any and all Virtuemart sef urls, meta data AND page titles - the most important of all! Plus Open graph data and more. You can do this for Virtuemart just like for any extension on your site.
If you are in doubt, check out the 3rd screenshot from the left, just above, and you'll see the Page title edit field.
If on top of manually altering any title or metadata for Virtuemart, through sh404SEF backend, you want to programm your own plugin to do so with your own rules, you can develop such plugins following our extensive documentation to do so (/sh404sef/docs/how-do-i-write-a-sh404sef-plugin-for-my-component.html and /forum/developer/sh404sef/324-writing-a-sh404sef-plugin-the-basics.html).
Frankly, I have no idea what you are referring to here.