I just got a 2 ton Craftsman all aluminum jack from my wife and son for my B-day, and it is schweeet!! 42.5 pounds and slides under the SVX with no fuss !
My personal feelings are that the best you can afford at the moment is the way to go. I plan to pass on my old Craftsman 2-ton to whichever of my sons has a garage of his own first, this after 20+ years of reliable service. Jack stands are so cheap, why scrimp over $5-10?
Glenn