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.
Well, what can I say except they have amazing support and amazing components. If you got problem they will fix it as soon as possible. Looking to work with them in future.