I have been using Broadcast by TechJoomla for a while and when i decided to ditch Virtuemart for a simpler, more supported cart I decided to go with Quick2Cart. I have not been disappointed.
It is pretty easy to understand and set up. Their directions are top notch. Although nothing is ever perfect for me and we had some issues with the template and a couple other snags, the support was right there for me.
I am looking forward to the multi-cart integration with k2 or the tagging system which is suppose to be in the next release.
Overall, I love this cart and my members are finding it pretty self explanatory.
Great component to get free site traffic from satisfied members I have installed Invitex on Joomla 1.5 and had some troubles getting facebook plugin to work on J.15. I created a ticket and developers have investigated the issue and updated the code to work on my old joomla installation.
Now everything is working fine.