I'm using Artio JoomSEF since the version for Joomla 1.0.x and I must say, that is the most complete SEF component for Joomla. And I have tried them all. I used also Sh404SEF, but since the development went to a stall last year (I don't know how's the situation right now, since development of the component started again), I switched to the paid version of JoomSEF and never regreted this decision.
I also use the virtuemart extension and the combination just rocks - the automatic internal links feature introduced in v 3.6 just rocks. Keep up the good work.