Most of them are still virtuemart because even I have purchased Redshop, it is not Joomfishable.
It is a very stable version of virtuemart. With the occasional problems yet to solve e.g. product scroller inconsistency between browsers (yes support was requested before, last year). Support response is quick though, even though the problem may not be solved.
I will still use it for a single language only site, which is a narrow market. It was worth the cost last year when there were still many bugs in virtuemart, which seemed to have ironed out a bit this year.
There is a jomfish plugin for redSHOP - its in the 3rd party download area and have been for quite a while.
Cant use it on multilingual sites though. My first choice for a 'contact us' in most of my sites when a complex contact form is not required.