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.
The extension is easy to install and to configurate. It exactly works like it is discribed, so no surpises. If you read the documation carefully it is easy to get the extension working!
I had a problem and submitted a ticket to the support. They answered me a few hours later and also after I react they answered after a few minuts, thats what I call a professional support. They also fixed the problem with given admin details for me.
I'm happy that I chose this extension.