I have no problem with Joomla. In fact I think its a great robust platform that is easily scalable with the right designer and programmer on board.
I also know in terms of SEO, out of the box, its no WordPress. Nor is it as easy as adding a plugin and doing a few tweaks here and there and you are on your way. Joomla needs to be nurtured like a little puppy. It needs to be taught not to wee there, not to chew that or bite them. But with enough care, things can work and work really well.
One of the things I love about Joomla are the taxonomies and pagination thats build into the system. A Joomla site looks really cool on the SERP pages and as a default, stands out from other listings. See the example below:
In the above you can see that for the term “Chiropractor Chatswood” you have several listings in Google+ Local. The one with the arrow pointing to it is built in Joomla and you can see the difference.
But getting the most out of the Joomla platform takes some fine tuning, from HTAccess.txt file changes, module installations and Robots.txt amendments.
I would go through them all but I just read a fantastic article about it at SEOmoz and I strongly recommend you have a read and implement these 11 Joomla SEO strategies.