YES and NO!
They can give you total control over how your URLs are generated. BUT, they can also clear their list of URLs and rebuild them in a completely different way.
I've seen sites with thousands of 404 errors and htaccess files that are 10MB in size. That's the amount of data in most YouTube videos.
So the question is are they worth it? I strongly believe NOT, I don't believe SEF URLs are that important any more and the issues that third party Joomla SEF extensions cause are simply not worth the minimal gain you might benefit from having them.
SEF URLs Are Not As Important In SEO As They Once Were
View this article about - Search Engine Friendly URLs versus Human Friendly URLs (SEF URLs versus HF URLs)
This article highlights my opinion on SEF URLs, that they have little to no benefit especially when compared to humans wanting logic navigation, basically people want the page title, menu item and URL to all say the same thing, it's a trust thing.
All Top Level Menu Items Joomla
The human element is more valuable than the search engine element, in recent months I've seen absolute evidence that Google favours flat menus, basically every article a top level menu item. This can easily be achieved in Joomla because of the ability to use menu type 'menu alias', you can have a menu that appears to be multi levelled but is really all top level.
I predominantly use this on our Web Design Lancashire site, this does remove that human friendly element of my navigation, but the rankings in Google speak for themselves. If you build a menu navigation structure that is all top level and use menu aliases you have 100% control - 100% control of your URLs and absolutely no risk of your URLs suddenly changing and thousands of 404 error being recorded day in day out. This way of building your menu structure as opposed to using a third party SEF extension will not add to your htaccess file and slow your site down.
My opinion on third party Joomla SEF extensions is that they offer no real benefit to a competent Joomla user / web designer. Anyone who knows the Joomla system and builds websites with it does not need to use an extension to create the URLs they want, do not use them, if your developer tells you they are necessary for good clean URLs, then please ask them about the problems they cause:
- Excessive database queries
- Very slow loading pages
- Sudden loss of URLs leading to 404 errors
- Excessive htaccess files(not all but some add to htaccess - the first file read in Joomla)
- Upgrading SEF extension loses settings(all too often)
Work Around VirtueMart URL Issues
There is a combination of software that most developers would say you need to use an SEF extension, Joomla 1.5 and VirtueMart combine to create URLs that are simply unfathomable for search engines and humans, but Twitter does the same. There are occasions when we don't mind how a URL looks even if it's at a time when we're about to hand over our hard earned money. Make sure your site has done the hard work of getting the sale before sending the client to the product page, you can build your site to use Joomla to the max before the final link to VirtueMart for the sale. All your SEO and general optimisation done on core Joomla pages then use your menu to link to product pages avoiding VirtueMart category pages.
Joomla SEF URL Extensions Create More Problems Than They Solve
Every point of view in favour of third party Joomla SEF extensions can very easily be countered, not just with a list of reasons why they break sites, but also ways of doing what they do with core Joomla functionality.
Build your site properly and the URLs will be exactly how you want them, avoid bad URLs with VirtueMart and similar add-ons by creating core Joomla pages only going to the add-ons at the last step needed.
The negative affects of SEF extensions can greatly reduce your site's Google rankings, slow page load times and leave you with broken inbound links.
If you're thinking of using SEF extensions for better SEO strength, think again. They do the exact opposite and obviously the worst possible effect on your site is down time or broken inbound links.
Professional Joomla SEO services.